1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #include <stdio.h> 39 #include <string.h> 40 #include <inttypes.h> 41 42 #include "ble/le_device_db.h" 43 #include "ble/core.h" 44 #include "ble/sm.h" 45 #include "btstack_debug.h" 46 #include "btstack_event.h" 47 #include "btstack_linked_list.h" 48 #include "btstack_memory.h" 49 #include "gap.h" 50 #include "hci.h" 51 #include "l2cap.h" 52 53 #ifdef ENABLE_LE_SECURE_CONNECTIONS 54 #ifdef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT 55 #error "Support for DHKEY Support in HCI Controller not implemented yet. Please use software implementation" 56 #else 57 #define USE_MBEDTLS_FOR_ECDH 58 #endif 59 #endif 60 61 62 // Software ECDH implementation provided by mbedtls 63 #ifdef USE_MBEDTLS_FOR_ECDH 64 #include "mbedtls/config.h" 65 #include "mbedtls/platform.h" 66 #include "mbedtls/ecp.h" 67 #include "sm_mbedtls_allocator.h" 68 #endif 69 70 // 71 // SM internal types and globals 72 // 73 74 typedef enum { 75 DKG_W4_WORKING, 76 DKG_CALC_IRK, 77 DKG_W4_IRK, 78 DKG_CALC_DHK, 79 DKG_W4_DHK, 80 DKG_READY 81 } derived_key_generation_t; 82 83 typedef enum { 84 RAU_W4_WORKING, 85 RAU_IDLE, 86 RAU_GET_RANDOM, 87 RAU_W4_RANDOM, 88 RAU_GET_ENC, 89 RAU_W4_ENC, 90 RAU_SET_ADDRESS, 91 } random_address_update_t; 92 93 typedef enum { 94 CMAC_IDLE, 95 CMAC_CALC_SUBKEYS, 96 CMAC_W4_SUBKEYS, 97 CMAC_CALC_MI, 98 CMAC_W4_MI, 99 CMAC_CALC_MLAST, 100 CMAC_W4_MLAST 101 } cmac_state_t; 102 103 typedef enum { 104 JUST_WORKS, 105 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 106 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 107 OK_BOTH_INPUT, // Only input on both, both input PK 108 NK_BOTH_INPUT, // Only numerical compparison (yes/no) on on both sides 109 OOB // OOB available on both sides 110 } stk_generation_method_t; 111 112 typedef enum { 113 SM_USER_RESPONSE_IDLE, 114 SM_USER_RESPONSE_PENDING, 115 SM_USER_RESPONSE_CONFIRM, 116 SM_USER_RESPONSE_PASSKEY, 117 SM_USER_RESPONSE_DECLINE 118 } sm_user_response_t; 119 120 typedef enum { 121 SM_AES128_IDLE, 122 SM_AES128_ACTIVE 123 } sm_aes128_state_t; 124 125 typedef enum { 126 ADDRESS_RESOLUTION_IDLE, 127 ADDRESS_RESOLUTION_GENERAL, 128 ADDRESS_RESOLUTION_FOR_CONNECTION, 129 } address_resolution_mode_t; 130 131 typedef enum { 132 ADDRESS_RESOLUTION_SUCEEDED, 133 ADDRESS_RESOLUTION_FAILED, 134 } address_resolution_event_t; 135 136 typedef enum { 137 EC_KEY_GENERATION_IDLE, 138 EC_KEY_GENERATION_ACTIVE, 139 EC_KEY_GENERATION_DONE, 140 } ec_key_generation_state_t; 141 142 typedef enum { 143 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 0 144 } sm_state_var_t; 145 146 // 147 // GLOBAL DATA 148 // 149 150 static uint8_t test_use_fixed_local_csrk; 151 152 // configuration 153 static uint8_t sm_accepted_stk_generation_methods; 154 static uint8_t sm_max_encryption_key_size; 155 static uint8_t sm_min_encryption_key_size; 156 static uint8_t sm_auth_req = 0; 157 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 158 static uint8_t sm_slave_request_security; 159 #ifdef ENABLE_LE_SECURE_CONNECTIONS 160 static uint8_t sm_have_ec_keypair; 161 #endif 162 163 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 164 static sm_key_t sm_persistent_er; 165 static sm_key_t sm_persistent_ir; 166 167 // derived from sm_persistent_ir 168 static sm_key_t sm_persistent_dhk; 169 static sm_key_t sm_persistent_irk; 170 static uint8_t sm_persistent_irk_ready = 0; // used for testing 171 static derived_key_generation_t dkg_state; 172 173 // derived from sm_persistent_er 174 // .. 175 176 // random address update 177 static random_address_update_t rau_state; 178 static bd_addr_t sm_random_address; 179 180 // CMAC Calculation: General 181 static cmac_state_t sm_cmac_state; 182 static uint16_t sm_cmac_message_len; 183 static sm_key_t sm_cmac_k; 184 static sm_key_t sm_cmac_x; 185 static sm_key_t sm_cmac_m_last; 186 static uint8_t sm_cmac_block_current; 187 static uint8_t sm_cmac_block_count; 188 static uint8_t (*sm_cmac_get_byte)(uint16_t offset); 189 static void (*sm_cmac_done_handler)(uint8_t * hash); 190 191 // CMAC for ATT Signed Writes 192 static uint8_t sm_cmac_header[3]; 193 static const uint8_t * sm_cmac_message; 194 static uint8_t sm_cmac_sign_counter[4]; 195 196 // CMAC for Secure Connection functions 197 #ifdef ENABLE_LE_SECURE_CONNECTIONS 198 static sm_connection_t * sm_cmac_connection; 199 static uint8_t sm_cmac_sc_buffer[80]; 200 #endif 201 202 // resolvable private address lookup / CSRK calculation 203 static int sm_address_resolution_test; 204 static int sm_address_resolution_ah_calculation_active; 205 static uint8_t sm_address_resolution_addr_type; 206 static bd_addr_t sm_address_resolution_address; 207 static void * sm_address_resolution_context; 208 static address_resolution_mode_t sm_address_resolution_mode; 209 static btstack_linked_list_t sm_address_resolution_general_queue; 210 211 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 212 static sm_aes128_state_t sm_aes128_state; 213 static void * sm_aes128_context; 214 215 // random engine. store context (ususally sm_connection_t) 216 static void * sm_random_context; 217 218 // to receive hci events 219 static btstack_packet_callback_registration_t hci_event_callback_registration; 220 221 /* to dispatch sm event */ 222 static btstack_linked_list_t sm_event_handlers; 223 224 225 // Software ECDH implementation provided by mbedtls 226 #ifdef USE_MBEDTLS_FOR_ECDH 227 // group is always valid 228 static mbedtls_ecp_group mbedtls_ec_group; 229 static ec_key_generation_state_t ec_key_generation_state; 230 static uint8_t ec_qx[32]; 231 static uint8_t ec_qy[32]; 232 static uint8_t ec_d[32]; 233 #ifndef HAVE_MALLOC 234 // 4304 bytes with 73 allocations 235 #define MBEDTLS_ALLOC_BUFFER_SIZE (1300+23*sizeof(void *)) 236 static uint8_t mbedtls_memory_buffer[MBEDTLS_ALLOC_BUFFER_SIZE]; 237 #endif 238 #endif 239 240 // 241 // Volume 3, Part H, Chapter 24 242 // "Security shall be initiated by the Security Manager in the device in the master role. 243 // The device in the slave role shall be the responding device." 244 // -> master := initiator, slave := responder 245 // 246 247 // data needed for security setup 248 typedef struct sm_setup_context { 249 250 btstack_timer_source_t sm_timeout; 251 252 // used in all phases 253 uint8_t sm_pairing_failed_reason; 254 255 // user response, (Phase 1 and/or 2) 256 uint8_t sm_user_response; 257 uint8_t sm_keypress_notification; 258 259 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 260 int sm_key_distribution_send_set; 261 int sm_key_distribution_received_set; 262 263 // Phase 2 (Pairing over SMP) 264 stk_generation_method_t sm_stk_generation_method; 265 sm_key_t sm_tk; 266 uint8_t sm_use_secure_connections; 267 268 sm_key_t sm_c1_t3_value; // c1 calculation 269 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 270 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 271 sm_key_t sm_local_random; 272 sm_key_t sm_local_confirm; 273 sm_key_t sm_peer_random; 274 sm_key_t sm_peer_confirm; 275 uint8_t sm_m_addr_type; // address and type can be removed 276 uint8_t sm_s_addr_type; // '' 277 bd_addr_t sm_m_address; // '' 278 bd_addr_t sm_s_address; // '' 279 sm_key_t sm_ltk; 280 281 uint8_t sm_state_vars; 282 #ifdef ENABLE_LE_SECURE_CONNECTIONS 283 uint8_t sm_peer_qx[32]; // also stores random for EC key generation during init 284 uint8_t sm_peer_qy[32]; // '' 285 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 286 sm_key_t sm_local_nonce; // might be combined with sm_local_random 287 sm_key_t sm_peer_dhkey_check; 288 sm_key_t sm_local_dhkey_check; 289 sm_key_t sm_ra; 290 sm_key_t sm_rb; 291 sm_key_t sm_t; // used for f5 and h6 292 sm_key_t sm_mackey; 293 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 294 #endif 295 296 // Phase 3 297 298 // key distribution, we generate 299 uint16_t sm_local_y; 300 uint16_t sm_local_div; 301 uint16_t sm_local_ediv; 302 uint8_t sm_local_rand[8]; 303 sm_key_t sm_local_ltk; 304 sm_key_t sm_local_csrk; 305 sm_key_t sm_local_irk; 306 // sm_local_address/addr_type not needed 307 308 // key distribution, received from peer 309 uint16_t sm_peer_y; 310 uint16_t sm_peer_div; 311 uint16_t sm_peer_ediv; 312 uint8_t sm_peer_rand[8]; 313 sm_key_t sm_peer_ltk; 314 sm_key_t sm_peer_irk; 315 sm_key_t sm_peer_csrk; 316 uint8_t sm_peer_addr_type; 317 bd_addr_t sm_peer_address; 318 319 } sm_setup_context_t; 320 321 // 322 static sm_setup_context_t the_setup; 323 static sm_setup_context_t * setup = &the_setup; 324 325 // active connection - the one for which the_setup is used for 326 static uint16_t sm_active_connection = 0; 327 328 // @returns 1 if oob data is available 329 // stores oob data in provided 16 byte buffer if not null 330 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 331 332 // horizontal: initiator capabilities 333 // vertial: responder capabilities 334 static const stk_generation_method_t stk_generation_method [5] [5] = { 335 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 336 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 337 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 338 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 339 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 340 }; 341 342 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 343 #ifdef ENABLE_LE_SECURE_CONNECTIONS 344 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 345 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 346 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 347 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 348 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 349 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 350 }; 351 #endif 352 353 static void sm_run(void); 354 static void sm_done_for_handle(hci_con_handle_t con_handle); 355 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 356 static inline int sm_calc_actual_encryption_key_size(int other); 357 static int sm_validate_stk_generation_method(void); 358 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data); 359 360 static void log_info_hex16(const char * name, uint16_t value){ 361 log_info("%-6s 0x%04x", name, value); 362 } 363 364 // @returns 1 if all bytes are 0 365 static int sm_is_null(uint8_t * data, int size){ 366 int i; 367 for (i=0; i < size ; i++){ 368 if (data[i]) return 0; 369 } 370 return 1; 371 } 372 373 static int sm_is_null_random(uint8_t random[8]){ 374 return sm_is_null(random, 8); 375 } 376 377 static int sm_is_null_key(uint8_t * key){ 378 return sm_is_null(key, 16); 379 } 380 381 // Key utils 382 static void sm_reset_tk(void){ 383 int i; 384 for (i=0;i<16;i++){ 385 setup->sm_tk[i] = 0; 386 } 387 } 388 389 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 390 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 391 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 392 int i; 393 for (i = max_encryption_size ; i < 16 ; i++){ 394 key[15-i] = 0; 395 } 396 } 397 398 // SMP Timeout implementation 399 400 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 401 // the Security Manager Timer shall be reset and started. 402 // 403 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 404 // 405 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 406 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 407 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 408 // established. 409 410 static void sm_timeout_handler(btstack_timer_source_t * timer){ 411 log_info("SM timeout"); 412 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 413 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 414 sm_done_for_handle(sm_conn->sm_handle); 415 416 // trigger handling of next ready connection 417 sm_run(); 418 } 419 static void sm_timeout_start(sm_connection_t * sm_conn){ 420 btstack_run_loop_remove_timer(&setup->sm_timeout); 421 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 422 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 423 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 424 btstack_run_loop_add_timer(&setup->sm_timeout); 425 } 426 static void sm_timeout_stop(void){ 427 btstack_run_loop_remove_timer(&setup->sm_timeout); 428 } 429 static void sm_timeout_reset(sm_connection_t * sm_conn){ 430 sm_timeout_stop(); 431 sm_timeout_start(sm_conn); 432 } 433 434 // end of sm timeout 435 436 // GAP Random Address updates 437 static gap_random_address_type_t gap_random_adress_type; 438 static btstack_timer_source_t gap_random_address_update_timer; 439 static uint32_t gap_random_adress_update_period; 440 441 static void gap_random_address_trigger(void){ 442 if (rau_state != RAU_IDLE) return; 443 log_info("gap_random_address_trigger"); 444 rau_state = RAU_GET_RANDOM; 445 sm_run(); 446 } 447 448 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 449 log_info("GAP Random Address Update due"); 450 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 451 btstack_run_loop_add_timer(&gap_random_address_update_timer); 452 gap_random_address_trigger(); 453 } 454 455 static void gap_random_address_update_start(void){ 456 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 457 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 458 btstack_run_loop_add_timer(&gap_random_address_update_timer); 459 } 460 461 static void gap_random_address_update_stop(void){ 462 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 463 } 464 465 466 static void sm_random_start(void * context){ 467 sm_random_context = context; 468 hci_send_cmd(&hci_le_rand); 469 } 470 471 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 472 // context is made availabe to aes128 result handler by this 473 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 474 sm_aes128_state = SM_AES128_ACTIVE; 475 sm_key_t key_flipped, plaintext_flipped; 476 reverse_128(key, key_flipped); 477 reverse_128(plaintext, plaintext_flipped); 478 sm_aes128_context = context; 479 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 480 } 481 482 // ah(k,r) helper 483 // r = padding || r 484 // r - 24 bit value 485 static void sm_ah_r_prime(uint8_t r[3], sm_key_t r_prime){ 486 // r'= padding || r 487 memset(r_prime, 0, 16); 488 memcpy(&r_prime[13], r, 3); 489 } 490 491 // d1 helper 492 // d' = padding || r || d 493 // d,r - 16 bit values 494 static void sm_d1_d_prime(uint16_t d, uint16_t r, sm_key_t d1_prime){ 495 // d'= padding || r || d 496 memset(d1_prime, 0, 16); 497 big_endian_store_16(d1_prime, 12, r); 498 big_endian_store_16(d1_prime, 14, d); 499 } 500 501 // dm helper 502 // r’ = padding || r 503 // r - 64 bit value 504 static void sm_dm_r_prime(uint8_t r[8], sm_key_t r_prime){ 505 memset(r_prime, 0, 16); 506 memcpy(&r_prime[8], r, 8); 507 } 508 509 // calculate arguments for first AES128 operation in C1 function 510 static void sm_c1_t1(sm_key_t r, uint8_t preq[7], uint8_t pres[7], uint8_t iat, uint8_t rat, sm_key_t t1){ 511 512 // p1 = pres || preq || rat’ || iat’ 513 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 514 // cant octet of pres becomes the most significant octet of p1. 515 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 516 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 517 // p1 is 0x05000800000302070710000001010001." 518 519 sm_key_t p1; 520 reverse_56(pres, &p1[0]); 521 reverse_56(preq, &p1[7]); 522 p1[14] = rat; 523 p1[15] = iat; 524 log_info_key("p1", p1); 525 log_info_key("r", r); 526 527 // t1 = r xor p1 528 int i; 529 for (i=0;i<16;i++){ 530 t1[i] = r[i] ^ p1[i]; 531 } 532 log_info_key("t1", t1); 533 } 534 535 // calculate arguments for second AES128 operation in C1 function 536 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, sm_key_t t3){ 537 // p2 = padding || ia || ra 538 // "The least significant octet of ra becomes the least significant octet of p2 and 539 // the most significant octet of padding becomes the most significant octet of p2. 540 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 541 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 542 543 sm_key_t p2; 544 memset(p2, 0, 16); 545 memcpy(&p2[4], ia, 6); 546 memcpy(&p2[10], ra, 6); 547 log_info_key("p2", p2); 548 549 // c1 = e(k, t2_xor_p2) 550 int i; 551 for (i=0;i<16;i++){ 552 t3[i] = t2[i] ^ p2[i]; 553 } 554 log_info_key("t3", t3); 555 } 556 557 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, sm_key_t r_prime){ 558 log_info_key("r1", r1); 559 log_info_key("r2", r2); 560 memcpy(&r_prime[8], &r2[8], 8); 561 memcpy(&r_prime[0], &r1[8], 8); 562 } 563 564 #ifdef ENABLE_LE_SECURE_CONNECTIONS 565 // Software implementations of crypto toolbox for LE Secure Connection 566 // TODO: replace with code to use AES Engine of HCI Controller 567 typedef uint8_t sm_key24_t[3]; 568 typedef uint8_t sm_key56_t[7]; 569 typedef uint8_t sm_key256_t[32]; 570 571 #if 0 572 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){ 573 uint32_t rk[RKLENGTH(KEYBITS)]; 574 int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS); 575 rijndaelEncrypt(rk, nrounds, plaintext, cyphertext); 576 } 577 578 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){ 579 memcpy(k1, k0, 16); 580 sm_shift_left_by_one_bit_inplace(16, k1); 581 if (k0[0] & 0x80){ 582 k1[15] ^= 0x87; 583 } 584 memcpy(k2, k1, 16); 585 sm_shift_left_by_one_bit_inplace(16, k2); 586 if (k1[0] & 0x80){ 587 k2[15] ^= 0x87; 588 } 589 } 590 591 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){ 592 sm_key_t k0, k1, k2, zero; 593 memset(zero, 0, 16); 594 595 aes128_calc_cyphertext(key, zero, k0); 596 calc_subkeys(k0, k1, k2); 597 598 int cmac_block_count = (cmac_message_len + 15) / 16; 599 600 // step 3: .. 601 if (cmac_block_count==0){ 602 cmac_block_count = 1; 603 } 604 605 // step 4: set m_last 606 sm_key_t cmac_m_last; 607 int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0; 608 int i; 609 if (sm_cmac_last_block_complete){ 610 for (i=0;i<16;i++){ 611 cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i]; 612 } 613 } else { 614 int valid_octets_in_last_block = cmac_message_len & 0x0f; 615 for (i=0;i<16;i++){ 616 if (i < valid_octets_in_last_block){ 617 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i]; 618 continue; 619 } 620 if (i == valid_octets_in_last_block){ 621 cmac_m_last[i] = 0x80 ^ k2[i]; 622 continue; 623 } 624 cmac_m_last[i] = k2[i]; 625 } 626 } 627 628 // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count); 629 // LOG_KEY(cmac_m_last); 630 631 // Step 5 632 sm_key_t cmac_x; 633 memset(cmac_x, 0, 16); 634 635 // Step 6 636 sm_key_t sm_cmac_y; 637 for (int block = 0 ; block < cmac_block_count-1 ; block++){ 638 for (i=0;i<16;i++){ 639 sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i]; 640 } 641 aes128_calc_cyphertext(key, sm_cmac_y, cmac_x); 642 } 643 for (i=0;i<16;i++){ 644 sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i]; 645 } 646 647 // Step 7 648 aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac); 649 } 650 #endif 651 #endif 652 653 static void sm_setup_event_base(uint8_t * event, int event_size, uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 654 event[0] = type; 655 event[1] = event_size - 2; 656 little_endian_store_16(event, 2, con_handle); 657 event[4] = addr_type; 658 reverse_bd_addr(address, &event[5]); 659 } 660 661 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 662 // dispatch to all event handlers 663 btstack_linked_list_iterator_t it; 664 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 665 while (btstack_linked_list_iterator_has_next(&it)){ 666 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 667 entry->callback(packet_type, 0, packet, size); 668 } 669 } 670 671 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 672 uint8_t event[11]; 673 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 674 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 675 } 676 677 static void sm_notify_client_passkey(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint32_t passkey){ 678 uint8_t event[15]; 679 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 680 little_endian_store_32(event, 11, passkey); 681 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 682 } 683 684 static void sm_notify_client_index(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint16_t index){ 685 uint8_t event[13]; 686 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 687 little_endian_store_16(event, 11, index); 688 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 689 } 690 691 static void sm_notify_client_authorization(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint8_t result){ 692 693 uint8_t event[18]; 694 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 695 event[11] = result; 696 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 697 } 698 699 // decide on stk generation based on 700 // - pairing request 701 // - io capabilities 702 // - OOB data availability 703 static void sm_setup_tk(void){ 704 705 // default: just works 706 setup->sm_stk_generation_method = JUST_WORKS; 707 708 #ifdef ENABLE_LE_SECURE_CONNECTIONS 709 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 710 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 711 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 712 memset(setup->sm_ra, 0, 16); 713 memset(setup->sm_rb, 0, 16); 714 #else 715 setup->sm_use_secure_connections = 0; 716 #endif 717 718 // If both devices have not set the MITM option in the Authentication Requirements 719 // Flags, then the IO capabilities shall be ignored and the Just Works association 720 // model shall be used. 721 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 722 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 723 log_info("SM: MITM not required by both -> JUST WORKS"); 724 return; 725 } 726 727 // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient 728 729 // If both devices have out of band authentication data, then the Authentication 730 // Requirements Flags shall be ignored when selecting the pairing method and the 731 // Out of Band pairing method shall be used. 732 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 733 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 734 log_info("SM: have OOB data"); 735 log_info_key("OOB", setup->sm_tk); 736 setup->sm_stk_generation_method = OOB; 737 return; 738 } 739 740 // Reset TK as it has been setup in sm_init_setup 741 sm_reset_tk(); 742 743 // Also use just works if unknown io capabilites 744 if ((sm_pairing_packet_get_io_capability(setup->sm_m_preq) > IO_CAPABILITY_KEYBOARD_DISPLAY) || (sm_pairing_packet_get_io_capability(setup->sm_s_pres) > IO_CAPABILITY_KEYBOARD_DISPLAY)){ 745 return; 746 } 747 748 // Otherwise the IO capabilities of the devices shall be used to determine the 749 // pairing method as defined in Table 2.4. 750 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 751 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 752 753 #ifdef ENABLE_LE_SECURE_CONNECTIONS 754 // table not define by default 755 if (setup->sm_use_secure_connections){ 756 generation_method = stk_generation_method_with_secure_connection; 757 } 758 #endif 759 setup->sm_stk_generation_method = generation_method[sm_pairing_packet_get_io_capability(setup->sm_s_pres)][sm_pairing_packet_get_io_capability(setup->sm_m_preq)]; 760 761 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 762 sm_pairing_packet_get_io_capability(setup->sm_m_preq), sm_pairing_packet_get_io_capability(setup->sm_s_pres), setup->sm_stk_generation_method); 763 } 764 765 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 766 int flags = 0; 767 if (key_set & SM_KEYDIST_ENC_KEY){ 768 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 769 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 770 } 771 if (key_set & SM_KEYDIST_ID_KEY){ 772 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 773 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 774 } 775 if (key_set & SM_KEYDIST_SIGN){ 776 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 777 } 778 return flags; 779 } 780 781 static void sm_setup_key_distribution(uint8_t key_set){ 782 setup->sm_key_distribution_received_set = 0; 783 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 784 } 785 786 // CSRK Key Lookup 787 788 789 static int sm_address_resolution_idle(void){ 790 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 791 } 792 793 static void sm_address_resolution_start_lookup(uint8_t addr_type, hci_con_handle_t con_handle, bd_addr_t addr, address_resolution_mode_t mode, void * context){ 794 memcpy(sm_address_resolution_address, addr, 6); 795 sm_address_resolution_addr_type = addr_type; 796 sm_address_resolution_test = 0; 797 sm_address_resolution_mode = mode; 798 sm_address_resolution_context = context; 799 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 800 } 801 802 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 803 // check if already in list 804 btstack_linked_list_iterator_t it; 805 sm_lookup_entry_t * entry; 806 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 807 while(btstack_linked_list_iterator_has_next(&it)){ 808 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 809 if (entry->address_type != address_type) continue; 810 if (memcmp(entry->address, address, 6)) continue; 811 // already in list 812 return BTSTACK_BUSY; 813 } 814 entry = btstack_memory_sm_lookup_entry_get(); 815 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 816 entry->address_type = (bd_addr_type_t) address_type; 817 memcpy(entry->address, address, 6); 818 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 819 sm_run(); 820 return 0; 821 } 822 823 // CMAC Implementation using AES128 engine 824 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 825 int i; 826 int carry = 0; 827 for (i=len-1; i >= 0 ; i--){ 828 int new_carry = data[i] >> 7; 829 data[i] = data[i] << 1 | carry; 830 carry = new_carry; 831 } 832 } 833 834 // while x_state++ for an enum is possible in C, it isn't in C++. we use this helpers to avoid compile errors for now 835 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 836 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 837 } 838 static inline void dkg_next_state(void){ 839 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 840 } 841 static inline void rau_next_state(void){ 842 rau_state = (random_address_update_t) (((int)rau_state) + 1); 843 } 844 845 // CMAC calculation using AES Engine 846 847 static inline void sm_cmac_next_state(void){ 848 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 849 } 850 851 static int sm_cmac_last_block_complete(void){ 852 if (sm_cmac_message_len == 0) return 0; 853 return (sm_cmac_message_len & 0x0f) == 0; 854 } 855 856 int sm_cmac_ready(void){ 857 return sm_cmac_state == CMAC_IDLE; 858 } 859 860 // generic cmac calculation 861 void sm_cmac_general_start(const sm_key_t key, uint16_t message_len, uint8_t (*get_byte_callback)(uint16_t offset), void (*done_callback)(uint8_t hash[8])){ 862 // Generalized CMAC 863 memcpy(sm_cmac_k, key, 16); 864 memset(sm_cmac_x, 0, 16); 865 sm_cmac_block_current = 0; 866 sm_cmac_message_len = message_len; 867 sm_cmac_done_handler = done_callback; 868 sm_cmac_get_byte = get_byte_callback; 869 870 // step 2: n := ceil(len/const_Bsize); 871 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 872 873 // step 3: .. 874 if (sm_cmac_block_count==0){ 875 sm_cmac_block_count = 1; 876 } 877 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 878 879 // first, we need to compute l for k1, k2, and m_last 880 sm_cmac_state = CMAC_CALC_SUBKEYS; 881 882 // let's go 883 sm_run(); 884 } 885 886 // cmac for ATT Message signing 887 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 888 if (offset >= sm_cmac_message_len) { 889 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 890 return 0; 891 } 892 893 offset = sm_cmac_message_len - 1 - offset; 894 895 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 896 if (offset < 3){ 897 return sm_cmac_header[offset]; 898 } 899 int actual_message_len_incl_header = sm_cmac_message_len - 4; 900 if (offset < actual_message_len_incl_header){ 901 return sm_cmac_message[offset - 3]; 902 } 903 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 904 } 905 906 void sm_cmac_signed_write_start(const sm_key_t k, uint8_t opcode, hci_con_handle_t con_handle, uint16_t message_len, const uint8_t * message, uint32_t sign_counter, void (*done_handler)(uint8_t * hash)){ 907 // ATT Message Signing 908 sm_cmac_header[0] = opcode; 909 little_endian_store_16(sm_cmac_header, 1, con_handle); 910 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 911 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 912 sm_cmac_message = message; 913 sm_cmac_general_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 914 } 915 916 917 static void sm_cmac_handle_aes_engine_ready(void){ 918 switch (sm_cmac_state){ 919 case CMAC_CALC_SUBKEYS: { 920 sm_key_t const_zero; 921 memset(const_zero, 0, 16); 922 sm_cmac_next_state(); 923 sm_aes128_start(sm_cmac_k, const_zero, NULL); 924 break; 925 } 926 case CMAC_CALC_MI: { 927 int j; 928 sm_key_t y; 929 for (j=0;j<16;j++){ 930 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 931 } 932 sm_cmac_block_current++; 933 sm_cmac_next_state(); 934 sm_aes128_start(sm_cmac_k, y, NULL); 935 break; 936 } 937 case CMAC_CALC_MLAST: { 938 int i; 939 sm_key_t y; 940 for (i=0;i<16;i++){ 941 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 942 } 943 log_info_key("Y", y); 944 sm_cmac_block_current++; 945 sm_cmac_next_state(); 946 sm_aes128_start(sm_cmac_k, y, NULL); 947 break; 948 } 949 default: 950 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 951 break; 952 } 953 } 954 955 static void sm_cmac_handle_encryption_result(sm_key_t data){ 956 switch (sm_cmac_state){ 957 case CMAC_W4_SUBKEYS: { 958 sm_key_t k1; 959 memcpy(k1, data, 16); 960 sm_shift_left_by_one_bit_inplace(16, k1); 961 if (data[0] & 0x80){ 962 k1[15] ^= 0x87; 963 } 964 sm_key_t k2; 965 memcpy(k2, k1, 16); 966 sm_shift_left_by_one_bit_inplace(16, k2); 967 if (k1[0] & 0x80){ 968 k2[15] ^= 0x87; 969 } 970 971 log_info_key("k", sm_cmac_k); 972 log_info_key("k1", k1); 973 log_info_key("k2", k2); 974 975 // step 4: set m_last 976 int i; 977 if (sm_cmac_last_block_complete()){ 978 for (i=0;i<16;i++){ 979 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 980 } 981 } else { 982 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 983 for (i=0;i<16;i++){ 984 if (i < valid_octets_in_last_block){ 985 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 986 continue; 987 } 988 if (i == valid_octets_in_last_block){ 989 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 990 continue; 991 } 992 sm_cmac_m_last[i] = k2[i]; 993 } 994 } 995 996 // next 997 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 998 break; 999 } 1000 case CMAC_W4_MI: 1001 memcpy(sm_cmac_x, data, 16); 1002 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1003 break; 1004 case CMAC_W4_MLAST: 1005 // done 1006 log_info("Setting CMAC Engine to IDLE"); 1007 sm_cmac_state = CMAC_IDLE; 1008 log_info_key("CMAC", data); 1009 sm_cmac_done_handler(data); 1010 break; 1011 default: 1012 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1013 break; 1014 } 1015 } 1016 1017 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1018 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1019 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1020 switch (setup->sm_stk_generation_method){ 1021 case PK_RESP_INPUT: 1022 if (sm_conn->sm_role){ 1023 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1024 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1025 } else { 1026 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1027 } 1028 break; 1029 case PK_INIT_INPUT: 1030 if (sm_conn->sm_role){ 1031 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1032 } else { 1033 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1034 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1035 } 1036 break; 1037 case OK_BOTH_INPUT: 1038 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1039 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1040 break; 1041 case NK_BOTH_INPUT: 1042 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1043 sm_notify_client_passkey(SM_EVENT_NUMERIC_COMPARISON_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1044 break; 1045 case JUST_WORKS: 1046 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1047 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1048 break; 1049 case OOB: 1050 // client already provided OOB data, let's skip notification. 1051 break; 1052 } 1053 } 1054 1055 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1056 int recv_flags; 1057 if (sm_conn->sm_role){ 1058 // slave / responder 1059 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1060 } else { 1061 // master / initiator 1062 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1063 } 1064 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1065 return recv_flags == setup->sm_key_distribution_received_set; 1066 } 1067 1068 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1069 if (sm_active_connection == con_handle){ 1070 sm_timeout_stop(); 1071 sm_active_connection = 0; 1072 log_info("sm: connection 0x%x released setup context", con_handle); 1073 } 1074 } 1075 1076 static int sm_key_distribution_flags_for_auth_req(void){ 1077 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 1078 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1079 // encryption information only if bonding requested 1080 flags |= SM_KEYDIST_ENC_KEY; 1081 } 1082 return flags; 1083 } 1084 1085 static void sm_reset_setup(void){ 1086 // fill in sm setup 1087 setup->sm_state_vars = 0; 1088 setup->sm_keypress_notification = 0xff; 1089 sm_reset_tk(); 1090 } 1091 1092 static void sm_init_setup(sm_connection_t * sm_conn){ 1093 1094 // fill in sm setup 1095 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1096 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1097 1098 // query client for OOB data 1099 int have_oob_data = 0; 1100 if (sm_get_oob_data) { 1101 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1102 } 1103 1104 sm_pairing_packet_t * local_packet; 1105 if (sm_conn->sm_role){ 1106 // slave 1107 local_packet = &setup->sm_s_pres; 1108 gap_advertisements_get_address(&setup->sm_s_addr_type, setup->sm_s_address); 1109 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1110 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1111 } else { 1112 // master 1113 local_packet = &setup->sm_m_preq; 1114 gap_advertisements_get_address(&setup->sm_m_addr_type, setup->sm_m_address); 1115 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1116 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1117 1118 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1119 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1120 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1121 } 1122 1123 uint8_t auth_req = sm_auth_req; 1124 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1125 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1126 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1127 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1128 } 1129 1130 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1131 1132 sm_pairing_packet_t * remote_packet; 1133 int remote_key_request; 1134 if (sm_conn->sm_role){ 1135 // slave / responder 1136 remote_packet = &setup->sm_m_preq; 1137 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1138 } else { 1139 // master / initiator 1140 remote_packet = &setup->sm_s_pres; 1141 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1142 } 1143 1144 // check key size 1145 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1146 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1147 1148 // decide on STK generation method 1149 sm_setup_tk(); 1150 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1151 1152 // check if STK generation method is acceptable by client 1153 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1154 1155 // identical to responder 1156 sm_setup_key_distribution(remote_key_request); 1157 1158 // JUST WORKS doens't provide authentication 1159 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1160 1161 return 0; 1162 } 1163 1164 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1165 1166 // cache and reset context 1167 int matched_device_id = sm_address_resolution_test; 1168 address_resolution_mode_t mode = sm_address_resolution_mode; 1169 void * context = sm_address_resolution_context; 1170 1171 // reset context 1172 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1173 sm_address_resolution_context = NULL; 1174 sm_address_resolution_test = -1; 1175 hci_con_handle_t con_handle = 0; 1176 1177 sm_connection_t * sm_connection; 1178 sm_key_t ltk; 1179 switch (mode){ 1180 case ADDRESS_RESOLUTION_GENERAL: 1181 break; 1182 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1183 sm_connection = (sm_connection_t *) context; 1184 con_handle = sm_connection->sm_handle; 1185 switch (event){ 1186 case ADDRESS_RESOLUTION_SUCEEDED: 1187 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1188 sm_connection->sm_le_db_index = matched_device_id; 1189 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1190 if (sm_connection->sm_role) break; 1191 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1192 sm_connection->sm_security_request_received = 0; 1193 sm_connection->sm_bonding_requested = 0; 1194 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 1195 if (!sm_is_null_key(ltk)){ 1196 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1197 } else { 1198 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1199 } 1200 break; 1201 case ADDRESS_RESOLUTION_FAILED: 1202 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1203 if (sm_connection->sm_role) break; 1204 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1205 sm_connection->sm_security_request_received = 0; 1206 sm_connection->sm_bonding_requested = 0; 1207 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1208 break; 1209 } 1210 break; 1211 default: 1212 break; 1213 } 1214 1215 switch (event){ 1216 case ADDRESS_RESOLUTION_SUCEEDED: 1217 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1218 break; 1219 case ADDRESS_RESOLUTION_FAILED: 1220 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1221 break; 1222 } 1223 } 1224 1225 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1226 1227 int le_db_index = -1; 1228 1229 // lookup device based on IRK 1230 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1231 int i; 1232 for (i=0; i < le_device_db_count(); i++){ 1233 sm_key_t irk; 1234 bd_addr_t address; 1235 int address_type; 1236 le_device_db_info(i, &address_type, address, irk); 1237 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1238 log_info("sm: device found for IRK, updating"); 1239 le_db_index = i; 1240 break; 1241 } 1242 } 1243 } 1244 1245 // if not found, lookup via public address if possible 1246 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1247 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1248 int i; 1249 for (i=0; i < le_device_db_count(); i++){ 1250 bd_addr_t address; 1251 int address_type; 1252 le_device_db_info(i, &address_type, address, NULL); 1253 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1254 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1255 log_info("sm: device found for public address, updating"); 1256 le_db_index = i; 1257 break; 1258 } 1259 } 1260 } 1261 1262 // if not found, add to db 1263 if (le_db_index < 0) { 1264 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1265 } 1266 1267 if (le_db_index >= 0){ 1268 1269 // store local CSRK 1270 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1271 log_info("sm: store local CSRK"); 1272 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1273 le_device_db_local_counter_set(le_db_index, 0); 1274 } 1275 1276 // store remote CSRK 1277 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1278 log_info("sm: store remote CSRK"); 1279 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1280 le_device_db_remote_counter_set(le_db_index, 0); 1281 } 1282 1283 // store encryption information for secure connections: LTK generated by ECDH 1284 if (setup->sm_use_secure_connections){ 1285 log_info("sm: store SC LTK (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1286 uint8_t zero_rand[8]; 1287 memset(zero_rand, 0, 8); 1288 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1289 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1290 } 1291 1292 // store encryption infromation for legacy pairing: peer LTK, EDIV, RAND 1293 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1294 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1295 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1296 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1297 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1298 1299 } 1300 } 1301 1302 // keep le_db_index 1303 sm_conn->sm_le_db_index = le_db_index; 1304 } 1305 1306 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1307 setup->sm_pairing_failed_reason = reason; 1308 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1309 } 1310 1311 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1312 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1313 } 1314 1315 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1316 1317 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1318 static int sm_passkey_used(stk_generation_method_t method); 1319 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1320 1321 static void sm_log_ec_keypair(void){ 1322 log_info("Elliptic curve: d"); 1323 log_info_hexdump(ec_d,32); 1324 log_info("Elliptic curve: X"); 1325 log_info_hexdump(ec_qx,32); 1326 log_info("Elliptic curve: Y"); 1327 log_info_hexdump(ec_qy,32); 1328 } 1329 1330 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1331 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1332 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1333 } else { 1334 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1335 } 1336 } 1337 1338 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1339 if (sm_conn->sm_role){ 1340 // Responder 1341 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1342 } else { 1343 // Initiator role 1344 switch (setup->sm_stk_generation_method){ 1345 case JUST_WORKS: 1346 sm_sc_prepare_dhkey_check(sm_conn); 1347 break; 1348 1349 case NK_BOTH_INPUT: 1350 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1351 break; 1352 case PK_INIT_INPUT: 1353 case PK_RESP_INPUT: 1354 case OK_BOTH_INPUT: 1355 if (setup->sm_passkey_bit < 20) { 1356 sm_sc_start_calculating_local_confirm(sm_conn); 1357 } else { 1358 sm_sc_prepare_dhkey_check(sm_conn); 1359 } 1360 break; 1361 case OOB: 1362 // TODO: implement SC OOB 1363 break; 1364 } 1365 } 1366 } 1367 1368 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1369 return sm_cmac_sc_buffer[offset]; 1370 } 1371 1372 static void sm_sc_cmac_done(uint8_t * hash){ 1373 log_info("sm_sc_cmac_done: "); 1374 log_info_hexdump(hash, 16); 1375 1376 sm_connection_t * sm_conn = sm_cmac_connection; 1377 sm_cmac_connection = NULL; 1378 link_key_type_t link_key_type; 1379 1380 switch (sm_conn->sm_engine_state){ 1381 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1382 memcpy(setup->sm_local_confirm, hash, 16); 1383 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1384 break; 1385 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1386 // check 1387 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1388 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1389 break; 1390 } 1391 sm_sc_state_after_receiving_random(sm_conn); 1392 break; 1393 case SM_SC_W4_CALCULATE_G2: { 1394 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1395 big_endian_store_32(setup->sm_tk, 12, vab); 1396 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1397 sm_trigger_user_response(sm_conn); 1398 break; 1399 } 1400 case SM_SC_W4_CALCULATE_F5_SALT: 1401 memcpy(setup->sm_t, hash, 16); 1402 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1403 break; 1404 case SM_SC_W4_CALCULATE_F5_MACKEY: 1405 memcpy(setup->sm_mackey, hash, 16); 1406 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1407 break; 1408 case SM_SC_W4_CALCULATE_F5_LTK: 1409 memcpy(setup->sm_ltk, hash, 16); 1410 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1411 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1412 break; 1413 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1414 memcpy(setup->sm_local_dhkey_check, hash, 16); 1415 if (sm_conn->sm_role){ 1416 // responder 1417 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1418 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1419 } else { 1420 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1421 } 1422 } else { 1423 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1424 } 1425 break; 1426 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1427 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1428 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1429 break; 1430 } 1431 if (sm_conn->sm_role){ 1432 // responder 1433 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1434 } else { 1435 // initiator 1436 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1437 } 1438 break; 1439 case SM_SC_W4_CALCULATE_H6_ILK: 1440 memcpy(setup->sm_t, hash, 16); 1441 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1442 break; 1443 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1444 reverse_128(hash, setup->sm_t); 1445 link_key_type = sm_conn->sm_connection_authenticated ? 1446 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1447 if (sm_conn->sm_role){ 1448 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1449 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1450 } else { 1451 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1452 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1453 } 1454 sm_done_for_handle(sm_conn->sm_handle); 1455 break; 1456 default: 1457 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1458 break; 1459 } 1460 sm_run(); 1461 } 1462 1463 static void f4_engine(sm_connection_t * sm_conn, const sm_key256_t u, const sm_key256_t v, const sm_key_t x, uint8_t z){ 1464 const uint16_t message_len = 65; 1465 sm_cmac_connection = sm_conn; 1466 memcpy(sm_cmac_sc_buffer, u, 32); 1467 memcpy(sm_cmac_sc_buffer+32, v, 32); 1468 sm_cmac_sc_buffer[64] = z; 1469 log_info("f4 key"); 1470 log_info_hexdump(x, 16); 1471 log_info("f4 message"); 1472 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1473 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1474 } 1475 1476 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1477 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1478 static const uint8_t f5_length[] = { 0x01, 0x00}; 1479 1480 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1481 #ifdef USE_MBEDTLS_FOR_ECDH 1482 // da * Pb 1483 mbedtls_mpi d; 1484 mbedtls_ecp_point Q; 1485 mbedtls_ecp_point DH; 1486 mbedtls_mpi_init(&d); 1487 mbedtls_ecp_point_init(&Q); 1488 mbedtls_ecp_point_init(&DH); 1489 mbedtls_mpi_read_binary(&d, ec_d, 32); 1490 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 1491 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 1492 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 1493 mbedtls_ecp_mul(&mbedtls_ec_group, &DH, &d, &Q, NULL, NULL); 1494 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1495 mbedtls_mpi_free(&d); 1496 mbedtls_ecp_point_free(&Q); 1497 mbedtls_ecp_point_free(&DH); 1498 #endif 1499 log_info("dhkey"); 1500 log_info_hexdump(dhkey, 32); 1501 } 1502 1503 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1504 // calculate DHKEY 1505 sm_key256_t dhkey; 1506 sm_sc_calculate_dhkey(dhkey); 1507 1508 // calculate salt for f5 1509 const uint16_t message_len = 32; 1510 sm_cmac_connection = sm_conn; 1511 memcpy(sm_cmac_sc_buffer, dhkey, message_len); 1512 sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1513 } 1514 1515 static inline void f5_mackkey(sm_connection_t * sm_conn, sm_key_t t, const sm_key_t n1, const sm_key_t n2, const sm_key56_t a1, const sm_key56_t a2){ 1516 const uint16_t message_len = 53; 1517 sm_cmac_connection = sm_conn; 1518 1519 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1520 sm_cmac_sc_buffer[0] = 0; 1521 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1522 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1523 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1524 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1525 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1526 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1527 log_info("f5 key"); 1528 log_info_hexdump(t, 16); 1529 log_info("f5 message for MacKey"); 1530 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1531 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1532 } 1533 1534 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1535 sm_key56_t bd_addr_master, bd_addr_slave; 1536 bd_addr_master[0] = setup->sm_m_addr_type; 1537 bd_addr_slave[0] = setup->sm_s_addr_type; 1538 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1539 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1540 if (sm_conn->sm_role){ 1541 // responder 1542 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1543 } else { 1544 // initiator 1545 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1546 } 1547 } 1548 1549 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1550 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1551 const uint16_t message_len = 53; 1552 sm_cmac_connection = sm_conn; 1553 sm_cmac_sc_buffer[0] = 1; 1554 // 1..52 setup before 1555 log_info("f5 key"); 1556 log_info_hexdump(t, 16); 1557 log_info("f5 message for LTK"); 1558 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1559 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1560 } 1561 1562 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1563 f5_ltk(sm_conn, setup->sm_t); 1564 } 1565 1566 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w, const sm_key_t n1, const sm_key_t n2, const sm_key_t r, const sm_key24_t io_cap, const sm_key56_t a1, const sm_key56_t a2){ 1567 const uint16_t message_len = 65; 1568 sm_cmac_connection = sm_conn; 1569 memcpy(sm_cmac_sc_buffer, n1, 16); 1570 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1571 memcpy(sm_cmac_sc_buffer+32, r, 16); 1572 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1573 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1574 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1575 log_info("f6 key"); 1576 log_info_hexdump(w, 16); 1577 log_info("f6 message"); 1578 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1579 sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1580 } 1581 1582 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1583 // - U is 256 bits 1584 // - V is 256 bits 1585 // - X is 128 bits 1586 // - Y is 128 bits 1587 static void g2_engine(sm_connection_t * sm_conn, const sm_key256_t u, const sm_key256_t v, const sm_key_t x, const sm_key_t y){ 1588 const uint16_t message_len = 80; 1589 sm_cmac_connection = sm_conn; 1590 memcpy(sm_cmac_sc_buffer, u, 32); 1591 memcpy(sm_cmac_sc_buffer+32, v, 32); 1592 memcpy(sm_cmac_sc_buffer+64, y, 16); 1593 log_info("g2 key"); 1594 log_info_hexdump(x, 16); 1595 log_info("g2 message"); 1596 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1597 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1598 } 1599 1600 static void g2_calculate(sm_connection_t * sm_conn) { 1601 // calc Va if numeric comparison 1602 if (sm_conn->sm_role){ 1603 // responder 1604 g2_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, setup->sm_local_nonce);; 1605 } else { 1606 // initiator 1607 g2_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, setup->sm_peer_nonce); 1608 } 1609 } 1610 1611 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1612 uint8_t z = 0; 1613 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1614 // some form of passkey 1615 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1616 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1617 setup->sm_passkey_bit++; 1618 } 1619 f4_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, z); 1620 } 1621 1622 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1623 uint8_t z = 0; 1624 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1625 // some form of passkey 1626 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1627 // sm_passkey_bit was increased before sending confirm value 1628 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1629 } 1630 f4_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, z); 1631 } 1632 1633 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1634 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1635 } 1636 1637 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1638 // calculate DHKCheck 1639 sm_key56_t bd_addr_master, bd_addr_slave; 1640 bd_addr_master[0] = setup->sm_m_addr_type; 1641 bd_addr_slave[0] = setup->sm_s_addr_type; 1642 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1643 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1644 uint8_t iocap_a[3]; 1645 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1646 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1647 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1648 uint8_t iocap_b[3]; 1649 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1650 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1651 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1652 if (sm_conn->sm_role){ 1653 // responder 1654 f6_engine(sm_conn, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1655 } else { 1656 // initiator 1657 f6_engine(sm_conn, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1658 } 1659 } 1660 1661 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1662 // validate E = f6() 1663 sm_key56_t bd_addr_master, bd_addr_slave; 1664 bd_addr_master[0] = setup->sm_m_addr_type; 1665 bd_addr_slave[0] = setup->sm_s_addr_type; 1666 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1667 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1668 1669 uint8_t iocap_a[3]; 1670 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1671 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1672 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1673 uint8_t iocap_b[3]; 1674 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1675 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1676 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1677 if (sm_conn->sm_role){ 1678 // responder 1679 f6_engine(sm_conn, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1680 } else { 1681 // initiator 1682 f6_engine(sm_conn, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1683 } 1684 } 1685 1686 1687 // 1688 // Link Key Conversion Function h6 1689 // 1690 // h6(W, keyID) = AES-CMACW(keyID) 1691 // - W is 128 bits 1692 // - keyID is 32 bits 1693 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1694 const uint16_t message_len = 4; 1695 sm_cmac_connection = sm_conn; 1696 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1697 log_info("h6 key"); 1698 log_info_hexdump(w, 16); 1699 log_info("h6 message"); 1700 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1701 sm_cmac_general_start(w, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1702 } 1703 1704 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1705 h6_engine(sm_conn, setup->sm_ltk, 0x746D7031); // "tmp1" 1706 } 1707 1708 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1709 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1710 } 1711 1712 #endif 1713 1714 // key management legacy connections: 1715 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1716 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1717 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1718 // - responder reconnects: responder uses LTK receveived from master 1719 1720 // key management secure connections: 1721 // - both devices store same LTK from ECDH key exchange. 1722 1723 static void sm_load_security_info(sm_connection_t * sm_connection){ 1724 int encryption_key_size; 1725 int authenticated; 1726 int authorized; 1727 1728 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1729 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1730 &encryption_key_size, &authenticated, &authorized); 1731 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1732 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1733 sm_connection->sm_connection_authenticated = authenticated; 1734 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1735 } 1736 1737 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1738 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1739 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1740 // re-establish used key encryption size 1741 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1742 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1743 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1744 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1745 log_info("sm: received ltk request with key size %u, authenticated %u", 1746 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1747 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1748 } 1749 1750 static void sm_run(void){ 1751 1752 btstack_linked_list_iterator_t it; 1753 1754 // assert that we can send at least commands 1755 if (!hci_can_send_command_packet_now()) return; 1756 1757 // 1758 // non-connection related behaviour 1759 // 1760 1761 // distributed key generation 1762 switch (dkg_state){ 1763 case DKG_CALC_IRK: 1764 // already busy? 1765 if (sm_aes128_state == SM_AES128_IDLE) { 1766 // IRK = d1(IR, 1, 0) 1767 sm_key_t d1_prime; 1768 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1769 dkg_next_state(); 1770 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1771 return; 1772 } 1773 break; 1774 case DKG_CALC_DHK: 1775 // already busy? 1776 if (sm_aes128_state == SM_AES128_IDLE) { 1777 // DHK = d1(IR, 3, 0) 1778 sm_key_t d1_prime; 1779 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1780 dkg_next_state(); 1781 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1782 return; 1783 } 1784 break; 1785 default: 1786 break; 1787 } 1788 1789 #ifdef USE_MBEDTLS_FOR_ECDH 1790 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 1791 sm_random_start(NULL); 1792 return; 1793 } 1794 #endif 1795 1796 // random address updates 1797 switch (rau_state){ 1798 case RAU_GET_RANDOM: 1799 rau_next_state(); 1800 sm_random_start(NULL); 1801 return; 1802 case RAU_GET_ENC: 1803 // already busy? 1804 if (sm_aes128_state == SM_AES128_IDLE) { 1805 sm_key_t r_prime; 1806 sm_ah_r_prime(sm_random_address, r_prime); 1807 rau_next_state(); 1808 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1809 return; 1810 } 1811 break; 1812 case RAU_SET_ADDRESS: 1813 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1814 rau_state = RAU_IDLE; 1815 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1816 return; 1817 default: 1818 break; 1819 } 1820 1821 // CMAC 1822 switch (sm_cmac_state){ 1823 case CMAC_CALC_SUBKEYS: 1824 case CMAC_CALC_MI: 1825 case CMAC_CALC_MLAST: 1826 // already busy? 1827 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1828 sm_cmac_handle_aes_engine_ready(); 1829 return; 1830 default: 1831 break; 1832 } 1833 1834 // CSRK Lookup 1835 // -- if csrk lookup ready, find connection that require csrk lookup 1836 if (sm_address_resolution_idle()){ 1837 hci_connections_get_iterator(&it); 1838 while(btstack_linked_list_iterator_has_next(&it)){ 1839 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1840 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1841 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1842 // and start lookup 1843 sm_address_resolution_start_lookup(sm_connection->sm_peer_addr_type, sm_connection->sm_handle, sm_connection->sm_peer_address, ADDRESS_RESOLUTION_FOR_CONNECTION, sm_connection); 1844 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1845 break; 1846 } 1847 } 1848 } 1849 1850 // -- if csrk lookup ready, resolved addresses for received addresses 1851 if (sm_address_resolution_idle()) { 1852 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1853 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1854 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1855 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1856 btstack_memory_sm_lookup_entry_free(entry); 1857 } 1858 } 1859 1860 // -- Continue with CSRK device lookup by public or resolvable private address 1861 if (!sm_address_resolution_idle()){ 1862 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1863 while (sm_address_resolution_test < le_device_db_count()){ 1864 int addr_type; 1865 bd_addr_t addr; 1866 sm_key_t irk; 1867 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1868 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1869 1870 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1871 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1872 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1873 break; 1874 } 1875 1876 if (sm_address_resolution_addr_type == 0){ 1877 sm_address_resolution_test++; 1878 continue; 1879 } 1880 1881 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1882 1883 log_info("LE Device Lookup: calculate AH"); 1884 log_info_key("IRK", irk); 1885 1886 sm_key_t r_prime; 1887 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1888 sm_address_resolution_ah_calculation_active = 1; 1889 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1890 return; 1891 } 1892 1893 if (sm_address_resolution_test >= le_device_db_count()){ 1894 log_info("LE Device Lookup: not found"); 1895 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1896 } 1897 } 1898 1899 1900 // 1901 // active connection handling 1902 // -- use loop to handle next connection if lock on setup context is released 1903 1904 while (1) { 1905 1906 // Find connections that requires setup context and make active if no other is locked 1907 hci_connections_get_iterator(&it); 1908 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1909 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1910 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1911 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1912 int done = 1; 1913 int err; 1914 switch (sm_connection->sm_engine_state) { 1915 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1916 // send packet if possible, 1917 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1918 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 1919 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1920 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1921 } else { 1922 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1923 } 1924 // don't lock sxetup context yet 1925 done = 0; 1926 break; 1927 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1928 sm_reset_setup(); 1929 sm_init_setup(sm_connection); 1930 // recover pairing request 1931 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1932 err = sm_stk_generation_init(sm_connection); 1933 if (err){ 1934 setup->sm_pairing_failed_reason = err; 1935 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1936 break; 1937 } 1938 sm_timeout_start(sm_connection); 1939 // generate random number first, if we need to show passkey 1940 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 1941 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 1942 break; 1943 } 1944 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1945 break; 1946 case SM_INITIATOR_PH0_HAS_LTK: 1947 sm_reset_setup(); 1948 sm_load_security_info(sm_connection); 1949 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 1950 break; 1951 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 1952 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1953 switch (sm_connection->sm_irk_lookup_state){ 1954 case IRK_LOOKUP_SUCCEEDED: 1955 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 1956 sm_reset_setup(); 1957 sm_load_security_info(sm_connection); 1958 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 1959 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 1960 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 1961 break; 1962 } 1963 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 1964 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1965 // don't lock setup context yet 1966 done = 0; 1967 break; 1968 case IRK_LOOKUP_FAILED: 1969 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 1970 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1971 // don't lock setup context yet 1972 done = 0; 1973 break; 1974 default: 1975 // just wait until IRK lookup is completed 1976 // don't lock setup context yet 1977 done = 0; 1978 break; 1979 } 1980 #endif 1981 break; 1982 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 1983 sm_reset_setup(); 1984 sm_init_setup(sm_connection); 1985 sm_timeout_start(sm_connection); 1986 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 1987 break; 1988 default: 1989 done = 0; 1990 break; 1991 } 1992 if (done){ 1993 sm_active_connection = sm_connection->sm_handle; 1994 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 1995 } 1996 } 1997 1998 // 1999 // active connection handling 2000 // 2001 2002 if (sm_active_connection == 0) return; 2003 2004 // assert that we could send a SM PDU - not needed for all of the following 2005 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2006 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2007 return; 2008 } 2009 2010 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 2011 if (!connection) return; 2012 2013 // send keypress notifications 2014 if (setup->sm_keypress_notification != 0xff){ 2015 uint8_t buffer[2]; 2016 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2017 buffer[1] = setup->sm_keypress_notification; 2018 setup->sm_keypress_notification = 0xff; 2019 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2020 return; 2021 } 2022 2023 sm_key_t plaintext; 2024 int key_distribution_flags; 2025 2026 log_info("sm_run: state %u", connection->sm_engine_state); 2027 2028 // responding state 2029 switch (connection->sm_engine_state){ 2030 2031 // general 2032 case SM_GENERAL_SEND_PAIRING_FAILED: { 2033 uint8_t buffer[2]; 2034 buffer[0] = SM_CODE_PAIRING_FAILED; 2035 buffer[1] = setup->sm_pairing_failed_reason; 2036 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2037 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2038 sm_done_for_handle(connection->sm_handle); 2039 break; 2040 } 2041 2042 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2043 case SM_SC_W2_GET_RANDOM_A: 2044 sm_random_start(connection); 2045 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_A; 2046 break; 2047 case SM_SC_W2_GET_RANDOM_B: 2048 sm_random_start(connection); 2049 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_B; 2050 break; 2051 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2052 if (!sm_cmac_ready()) break; 2053 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2054 sm_sc_calculate_local_confirm(connection); 2055 break; 2056 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2057 if (!sm_cmac_ready()) break; 2058 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2059 sm_sc_calculate_remote_confirm(connection); 2060 break; 2061 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2062 if (!sm_cmac_ready()) break; 2063 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2064 sm_sc_calculate_f6_for_dhkey_check(connection); 2065 break; 2066 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2067 if (!sm_cmac_ready()) break; 2068 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2069 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2070 break; 2071 case SM_SC_W2_CALCULATE_F5_SALT: 2072 if (!sm_cmac_ready()) break; 2073 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2074 f5_calculate_salt(connection); 2075 break; 2076 case SM_SC_W2_CALCULATE_F5_MACKEY: 2077 if (!sm_cmac_ready()) break; 2078 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2079 f5_calculate_mackey(connection); 2080 break; 2081 case SM_SC_W2_CALCULATE_F5_LTK: 2082 if (!sm_cmac_ready()) break; 2083 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2084 f5_calculate_ltk(connection); 2085 break; 2086 case SM_SC_W2_CALCULATE_G2: 2087 if (!sm_cmac_ready()) break; 2088 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2089 g2_calculate(connection); 2090 break; 2091 case SM_SC_W2_CALCULATE_H6_ILK: 2092 if (!sm_cmac_ready()) break; 2093 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2094 h6_calculate_ilk(connection); 2095 break; 2096 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2097 if (!sm_cmac_ready()) break; 2098 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2099 h6_calculate_br_edr_link_key(connection); 2100 break; 2101 2102 #endif 2103 // initiator side 2104 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2105 sm_key_t peer_ltk_flipped; 2106 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2107 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2108 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2109 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2110 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2111 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2112 return; 2113 } 2114 2115 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2116 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2117 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2118 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2119 sm_timeout_reset(connection); 2120 break; 2121 2122 // responder side 2123 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2124 connection->sm_engine_state = SM_RESPONDER_IDLE; 2125 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2126 sm_done_for_handle(connection->sm_handle); 2127 return; 2128 2129 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2130 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2131 uint8_t buffer[65]; 2132 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2133 // 2134 reverse_256(ec_qx, &buffer[1]); 2135 reverse_256(ec_qy, &buffer[33]); 2136 2137 // stk generation method 2138 // passkey entry: notify app to show passkey or to request passkey 2139 switch (setup->sm_stk_generation_method){ 2140 case JUST_WORKS: 2141 case NK_BOTH_INPUT: 2142 if (connection->sm_role){ 2143 // responder 2144 sm_sc_start_calculating_local_confirm(connection); 2145 } else { 2146 // initiator 2147 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2148 } 2149 break; 2150 case PK_INIT_INPUT: 2151 case PK_RESP_INPUT: 2152 case OK_BOTH_INPUT: 2153 // use random TK for display 2154 memcpy(setup->sm_ra, setup->sm_tk, 16); 2155 memcpy(setup->sm_rb, setup->sm_tk, 16); 2156 setup->sm_passkey_bit = 0; 2157 2158 if (connection->sm_role){ 2159 // responder 2160 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2161 } else { 2162 // initiator 2163 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2164 } 2165 sm_trigger_user_response(connection); 2166 break; 2167 case OOB: 2168 // TODO: implement SC OOB 2169 break; 2170 } 2171 2172 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2173 sm_timeout_reset(connection); 2174 break; 2175 } 2176 case SM_SC_SEND_CONFIRMATION: { 2177 uint8_t buffer[17]; 2178 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2179 reverse_128(setup->sm_local_confirm, &buffer[1]); 2180 if (connection->sm_role){ 2181 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2182 } else { 2183 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2184 } 2185 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2186 sm_timeout_reset(connection); 2187 break; 2188 } 2189 case SM_SC_SEND_PAIRING_RANDOM: { 2190 uint8_t buffer[17]; 2191 buffer[0] = SM_CODE_PAIRING_RANDOM; 2192 reverse_128(setup->sm_local_nonce, &buffer[1]); 2193 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2194 if (connection->sm_role){ 2195 // responder 2196 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2197 } else { 2198 // initiator 2199 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2200 } 2201 } else { 2202 if (connection->sm_role){ 2203 // responder 2204 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2205 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2206 } else { 2207 sm_sc_prepare_dhkey_check(connection); 2208 } 2209 } else { 2210 // initiator 2211 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2212 } 2213 } 2214 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2215 sm_timeout_reset(connection); 2216 break; 2217 } 2218 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2219 uint8_t buffer[17]; 2220 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2221 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2222 2223 if (connection->sm_role){ 2224 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2225 } else { 2226 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2227 } 2228 2229 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2230 sm_timeout_reset(connection); 2231 break; 2232 } 2233 2234 #endif 2235 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2236 // echo initiator for now 2237 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2238 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2239 2240 if (setup->sm_use_secure_connections){ 2241 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2242 // skip LTK/EDIV for SC 2243 log_info("sm: dropping encryption information flag"); 2244 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2245 } else { 2246 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2247 } 2248 2249 sm_pairing_packet_set_initiator_key_distribution(setup->sm_s_pres, sm_pairing_packet_get_initiator_key_distribution(setup->sm_m_preq) & key_distribution_flags); 2250 sm_pairing_packet_set_responder_key_distribution(setup->sm_s_pres, sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq) & key_distribution_flags); 2251 // update key distribution after ENC was dropped 2252 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2253 2254 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2255 sm_timeout_reset(connection); 2256 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2257 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2258 sm_trigger_user_response(connection); 2259 } 2260 return; 2261 2262 case SM_PH2_SEND_PAIRING_RANDOM: { 2263 uint8_t buffer[17]; 2264 buffer[0] = SM_CODE_PAIRING_RANDOM; 2265 reverse_128(setup->sm_local_random, &buffer[1]); 2266 if (connection->sm_role){ 2267 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2268 } else { 2269 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2270 } 2271 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2272 sm_timeout_reset(connection); 2273 break; 2274 } 2275 2276 case SM_PH2_GET_RANDOM_TK: 2277 case SM_PH2_C1_GET_RANDOM_A: 2278 case SM_PH2_C1_GET_RANDOM_B: 2279 case SM_PH3_GET_RANDOM: 2280 case SM_PH3_GET_DIV: 2281 sm_next_responding_state(connection); 2282 sm_random_start(connection); 2283 return; 2284 2285 case SM_PH2_C1_GET_ENC_B: 2286 case SM_PH2_C1_GET_ENC_D: 2287 // already busy? 2288 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2289 sm_next_responding_state(connection); 2290 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2291 return; 2292 2293 case SM_PH3_LTK_GET_ENC: 2294 case SM_RESPONDER_PH4_LTK_GET_ENC: 2295 // already busy? 2296 if (sm_aes128_state == SM_AES128_IDLE) { 2297 sm_key_t d_prime; 2298 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2299 sm_next_responding_state(connection); 2300 sm_aes128_start(sm_persistent_er, d_prime, connection); 2301 return; 2302 } 2303 break; 2304 2305 case SM_PH3_CSRK_GET_ENC: 2306 // already busy? 2307 if (sm_aes128_state == SM_AES128_IDLE) { 2308 sm_key_t d_prime; 2309 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2310 sm_next_responding_state(connection); 2311 sm_aes128_start(sm_persistent_er, d_prime, connection); 2312 return; 2313 } 2314 break; 2315 2316 case SM_PH2_C1_GET_ENC_C: 2317 // already busy? 2318 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2319 // calculate m_confirm using aes128 engine - step 1 2320 sm_c1_t1(setup->sm_peer_random, (uint8_t*) &setup->sm_m_preq, (uint8_t*) &setup->sm_s_pres, setup->sm_m_addr_type, setup->sm_s_addr_type, plaintext); 2321 sm_next_responding_state(connection); 2322 sm_aes128_start(setup->sm_tk, plaintext, connection); 2323 break; 2324 case SM_PH2_C1_GET_ENC_A: 2325 // already busy? 2326 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2327 // calculate confirm using aes128 engine - step 1 2328 sm_c1_t1(setup->sm_local_random, (uint8_t*) &setup->sm_m_preq, (uint8_t*) &setup->sm_s_pres, setup->sm_m_addr_type, setup->sm_s_addr_type, plaintext); 2329 sm_next_responding_state(connection); 2330 sm_aes128_start(setup->sm_tk, plaintext, connection); 2331 break; 2332 case SM_PH2_CALC_STK: 2333 // already busy? 2334 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2335 // calculate STK 2336 if (connection->sm_role){ 2337 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2338 } else { 2339 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2340 } 2341 sm_next_responding_state(connection); 2342 sm_aes128_start(setup->sm_tk, plaintext, connection); 2343 break; 2344 case SM_PH3_Y_GET_ENC: 2345 // already busy? 2346 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2347 // PH3B2 - calculate Y from - enc 2348 // Y = dm(DHK, Rand) 2349 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2350 sm_next_responding_state(connection); 2351 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2352 return; 2353 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2354 uint8_t buffer[17]; 2355 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2356 reverse_128(setup->sm_local_confirm, &buffer[1]); 2357 if (connection->sm_role){ 2358 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2359 } else { 2360 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2361 } 2362 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2363 sm_timeout_reset(connection); 2364 return; 2365 } 2366 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2367 sm_key_t stk_flipped; 2368 reverse_128(setup->sm_ltk, stk_flipped); 2369 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2370 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2371 return; 2372 } 2373 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2374 sm_key_t stk_flipped; 2375 reverse_128(setup->sm_ltk, stk_flipped); 2376 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2377 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2378 return; 2379 } 2380 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2381 sm_key_t ltk_flipped; 2382 reverse_128(setup->sm_ltk, ltk_flipped); 2383 connection->sm_engine_state = SM_RESPONDER_IDLE; 2384 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2385 return; 2386 } 2387 case SM_RESPONDER_PH4_Y_GET_ENC: 2388 // already busy? 2389 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2390 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2391 // Y = dm(DHK, Rand) 2392 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2393 sm_next_responding_state(connection); 2394 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2395 return; 2396 2397 case SM_PH3_DISTRIBUTE_KEYS: 2398 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2399 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2400 uint8_t buffer[17]; 2401 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2402 reverse_128(setup->sm_ltk, &buffer[1]); 2403 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2404 sm_timeout_reset(connection); 2405 return; 2406 } 2407 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2408 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2409 uint8_t buffer[11]; 2410 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2411 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2412 reverse_64(setup->sm_local_rand, &buffer[3]); 2413 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2414 sm_timeout_reset(connection); 2415 return; 2416 } 2417 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2418 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2419 uint8_t buffer[17]; 2420 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2421 reverse_128(sm_persistent_irk, &buffer[1]); 2422 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2423 sm_timeout_reset(connection); 2424 return; 2425 } 2426 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2427 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2428 bd_addr_t local_address; 2429 uint8_t buffer[8]; 2430 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2431 gap_advertisements_get_address(&buffer[1], local_address); 2432 reverse_bd_addr(local_address, &buffer[2]); 2433 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2434 sm_timeout_reset(connection); 2435 return; 2436 } 2437 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2438 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2439 2440 // hack to reproduce test runs 2441 if (test_use_fixed_local_csrk){ 2442 memset(setup->sm_local_csrk, 0xcc, 16); 2443 } 2444 2445 uint8_t buffer[17]; 2446 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2447 reverse_128(setup->sm_local_csrk, &buffer[1]); 2448 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2449 sm_timeout_reset(connection); 2450 return; 2451 } 2452 2453 // keys are sent 2454 if (connection->sm_role){ 2455 // slave -> receive master keys if any 2456 if (sm_key_distribution_all_received(connection)){ 2457 sm_key_distribution_handle_all_received(connection); 2458 connection->sm_engine_state = SM_RESPONDER_IDLE; 2459 sm_done_for_handle(connection->sm_handle); 2460 } else { 2461 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2462 } 2463 } else { 2464 // master -> all done 2465 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2466 sm_done_for_handle(connection->sm_handle); 2467 } 2468 break; 2469 2470 default: 2471 break; 2472 } 2473 2474 // check again if active connection was released 2475 if (sm_active_connection) break; 2476 } 2477 } 2478 2479 // note: aes engine is ready as we just got the aes result 2480 static void sm_handle_encryption_result(uint8_t * data){ 2481 2482 sm_aes128_state = SM_AES128_IDLE; 2483 2484 if (sm_address_resolution_ah_calculation_active){ 2485 sm_address_resolution_ah_calculation_active = 0; 2486 // compare calulated address against connecting device 2487 uint8_t hash[3]; 2488 reverse_24(data, hash); 2489 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2490 log_info("LE Device Lookup: matched resolvable private address"); 2491 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2492 return; 2493 } 2494 // no match, try next 2495 sm_address_resolution_test++; 2496 return; 2497 } 2498 2499 switch (dkg_state){ 2500 case DKG_W4_IRK: 2501 reverse_128(data, sm_persistent_irk); 2502 log_info_key("irk", sm_persistent_irk); 2503 dkg_next_state(); 2504 return; 2505 case DKG_W4_DHK: 2506 reverse_128(data, sm_persistent_dhk); 2507 log_info_key("dhk", sm_persistent_dhk); 2508 dkg_next_state(); 2509 // SM Init Finished 2510 return; 2511 default: 2512 break; 2513 } 2514 2515 switch (rau_state){ 2516 case RAU_W4_ENC: 2517 reverse_24(data, &sm_random_address[3]); 2518 rau_next_state(); 2519 return; 2520 default: 2521 break; 2522 } 2523 2524 switch (sm_cmac_state){ 2525 case CMAC_W4_SUBKEYS: 2526 case CMAC_W4_MI: 2527 case CMAC_W4_MLAST: 2528 { 2529 sm_key_t t; 2530 reverse_128(data, t); 2531 sm_cmac_handle_encryption_result(t); 2532 } 2533 return; 2534 default: 2535 break; 2536 } 2537 2538 // retrieve sm_connection provided to sm_aes128_start_encryption 2539 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2540 if (!connection) return; 2541 switch (connection->sm_engine_state){ 2542 case SM_PH2_C1_W4_ENC_A: 2543 case SM_PH2_C1_W4_ENC_C: 2544 { 2545 sm_key_t t2; 2546 reverse_128(data, t2); 2547 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2548 } 2549 sm_next_responding_state(connection); 2550 return; 2551 case SM_PH2_C1_W4_ENC_B: 2552 reverse_128(data, setup->sm_local_confirm); 2553 log_info_key("c1!", setup->sm_local_confirm); 2554 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2555 return; 2556 case SM_PH2_C1_W4_ENC_D: 2557 { 2558 sm_key_t peer_confirm_test; 2559 reverse_128(data, peer_confirm_test); 2560 log_info_key("c1!", peer_confirm_test); 2561 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2562 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2563 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2564 return; 2565 } 2566 if (connection->sm_role){ 2567 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2568 } else { 2569 connection->sm_engine_state = SM_PH2_CALC_STK; 2570 } 2571 } 2572 return; 2573 case SM_PH2_W4_STK: 2574 reverse_128(data, setup->sm_ltk); 2575 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2576 log_info_key("stk", setup->sm_ltk); 2577 if (connection->sm_role){ 2578 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2579 } else { 2580 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2581 } 2582 return; 2583 case SM_PH3_Y_W4_ENC:{ 2584 sm_key_t y128; 2585 reverse_128(data, y128); 2586 setup->sm_local_y = big_endian_read_16(y128, 14); 2587 log_info_hex16("y", setup->sm_local_y); 2588 // PH3B3 - calculate EDIV 2589 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2590 log_info_hex16("ediv", setup->sm_local_ediv); 2591 // PH3B4 - calculate LTK - enc 2592 // LTK = d1(ER, DIV, 0)) 2593 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2594 return; 2595 } 2596 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2597 sm_key_t y128; 2598 reverse_128(data, y128); 2599 setup->sm_local_y = big_endian_read_16(y128, 14); 2600 log_info_hex16("y", setup->sm_local_y); 2601 2602 // PH3B3 - calculate DIV 2603 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2604 log_info_hex16("ediv", setup->sm_local_ediv); 2605 // PH3B4 - calculate LTK - enc 2606 // LTK = d1(ER, DIV, 0)) 2607 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2608 return; 2609 } 2610 case SM_PH3_LTK_W4_ENC: 2611 reverse_128(data, setup->sm_ltk); 2612 log_info_key("ltk", setup->sm_ltk); 2613 // calc CSRK next 2614 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2615 return; 2616 case SM_PH3_CSRK_W4_ENC: 2617 reverse_128(data, setup->sm_local_csrk); 2618 log_info_key("csrk", setup->sm_local_csrk); 2619 if (setup->sm_key_distribution_send_set){ 2620 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2621 } else { 2622 // no keys to send, just continue 2623 if (connection->sm_role){ 2624 // slave -> receive master keys 2625 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2626 } else { 2627 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2628 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2629 } else { 2630 // master -> all done 2631 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2632 sm_done_for_handle(connection->sm_handle); 2633 } 2634 } 2635 } 2636 return; 2637 case SM_RESPONDER_PH4_LTK_W4_ENC: 2638 reverse_128(data, setup->sm_ltk); 2639 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2640 log_info_key("ltk", setup->sm_ltk); 2641 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2642 return; 2643 default: 2644 break; 2645 } 2646 } 2647 2648 #ifdef USE_MBEDTLS_FOR_ECDH 2649 2650 static int sm_generate_f_rng(void * context, unsigned char * buffer, size_t size){ 2651 int offset = setup->sm_passkey_bit; 2652 log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset); 2653 while (size) { 2654 if (offset < 32){ 2655 *buffer++ = setup->sm_peer_qx[offset++]; 2656 } else { 2657 *buffer++ = setup->sm_peer_qx[offset++ - 32]; 2658 } 2659 size--; 2660 } 2661 setup->sm_passkey_bit = offset; 2662 return 0; 2663 } 2664 #endif 2665 2666 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2667 static void sm_handle_random_result(uint8_t * data){ 2668 2669 #ifdef USE_MBEDTLS_FOR_ECDH 2670 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 2671 int num_bytes = setup->sm_passkey_bit; 2672 if (num_bytes < 32){ 2673 memcpy(&setup->sm_peer_qx[num_bytes], data, 8); 2674 } else { 2675 memcpy(&setup->sm_peer_qx[num_bytes-32], data, 8); 2676 } 2677 num_bytes += 8; 2678 setup->sm_passkey_bit = num_bytes; 2679 2680 if (num_bytes >= 64){ 2681 // generate EC key 2682 setup->sm_passkey_bit = 0; 2683 mbedtls_mpi d; 2684 mbedtls_ecp_point P; 2685 mbedtls_mpi_init(&d); 2686 mbedtls_ecp_point_init(&P); 2687 int res = mbedtls_ecp_gen_keypair(&mbedtls_ec_group, &d, &P, &sm_generate_f_rng, NULL); 2688 log_info("gen keypair %x", res); 2689 mbedtls_mpi_write_binary(&P.X, ec_qx, 32); 2690 mbedtls_mpi_write_binary(&P.Y, ec_qy, 32); 2691 mbedtls_mpi_write_binary(&d, ec_d, 32); 2692 mbedtls_ecp_point_free(&P); 2693 mbedtls_mpi_free(&d); 2694 ec_key_generation_state = EC_KEY_GENERATION_DONE; 2695 sm_log_ec_keypair(); 2696 2697 #if 0 2698 printf("test dhkey check\n"); 2699 sm_key256_t dhkey; 2700 memcpy(setup->sm_peer_qx, ec_qx, 32); 2701 memcpy(setup->sm_peer_qy, ec_qy, 32); 2702 sm_sc_calculate_dhkey(dhkey); 2703 #endif 2704 2705 } 2706 } 2707 #endif 2708 2709 switch (rau_state){ 2710 case RAU_W4_RANDOM: 2711 // non-resolvable vs. resolvable 2712 switch (gap_random_adress_type){ 2713 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2714 // resolvable: use random as prand and calc address hash 2715 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2716 memcpy(sm_random_address, data, 3); 2717 sm_random_address[0] &= 0x3f; 2718 sm_random_address[0] |= 0x40; 2719 rau_state = RAU_GET_ENC; 2720 break; 2721 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2722 default: 2723 // "The two most significant bits of the address shall be equal to ‘0’"" 2724 memcpy(sm_random_address, data, 6); 2725 sm_random_address[0] &= 0x3f; 2726 rau_state = RAU_SET_ADDRESS; 2727 break; 2728 } 2729 return; 2730 default: 2731 break; 2732 } 2733 2734 // retrieve sm_connection provided to sm_random_start 2735 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2736 if (!connection) return; 2737 switch (connection->sm_engine_state){ 2738 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2739 case SM_SC_W4_GET_RANDOM_A: 2740 memcpy(&setup->sm_local_nonce[0], data, 8); 2741 connection->sm_engine_state = SM_SC_W2_GET_RANDOM_B; 2742 break; 2743 case SM_SC_W4_GET_RANDOM_B: 2744 memcpy(&setup->sm_local_nonce[8], data, 8); 2745 // initiator & jw/nc -> send pairing random 2746 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2747 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2748 break; 2749 } else { 2750 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2751 } 2752 break; 2753 #endif 2754 2755 case SM_PH2_W4_RANDOM_TK: 2756 { 2757 // map random to 0-999999 without speding much cycles on a modulus operation 2758 uint32_t tk = little_endian_read_32(data,0); 2759 tk = tk & 0xfffff; // 1048575 2760 if (tk >= 999999){ 2761 tk = tk - 999999; 2762 } 2763 sm_reset_tk(); 2764 big_endian_store_32(setup->sm_tk, 12, tk); 2765 if (connection->sm_role){ 2766 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2767 } else { 2768 if (setup->sm_use_secure_connections){ 2769 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2770 } else { 2771 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2772 sm_trigger_user_response(connection); 2773 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2774 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2775 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2776 } 2777 } 2778 } 2779 return; 2780 } 2781 case SM_PH2_C1_W4_RANDOM_A: 2782 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2783 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2784 return; 2785 case SM_PH2_C1_W4_RANDOM_B: 2786 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2787 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2788 return; 2789 case SM_PH3_W4_RANDOM: 2790 reverse_64(data, setup->sm_local_rand); 2791 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2792 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2793 // no db for authenticated flag hack: store flag in bit 4 of LSB 2794 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2795 connection->sm_engine_state = SM_PH3_GET_DIV; 2796 return; 2797 case SM_PH3_W4_DIV: 2798 // use 16 bit from random value as div 2799 setup->sm_local_div = big_endian_read_16(data, 0); 2800 log_info_hex16("div", setup->sm_local_div); 2801 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2802 return; 2803 default: 2804 break; 2805 } 2806 } 2807 2808 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2809 2810 sm_connection_t * sm_conn; 2811 hci_con_handle_t con_handle; 2812 2813 switch (packet_type) { 2814 2815 case HCI_EVENT_PACKET: 2816 switch (hci_event_packet_get_type(packet)) { 2817 2818 case BTSTACK_EVENT_STATE: 2819 // bt stack activated, get started 2820 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2821 log_info("HCI Working!"); 2822 2823 // set local addr for le device db 2824 bd_addr_t local_bd_addr; 2825 gap_local_bd_addr(local_bd_addr); 2826 le_device_db_set_local_bd_addr(local_bd_addr); 2827 2828 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2829 rau_state = RAU_IDLE; 2830 #ifdef USE_MBEDTLS_FOR_ECDH 2831 if (!sm_have_ec_keypair){ 2832 setup->sm_passkey_bit = 0; 2833 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 2834 } 2835 #endif 2836 sm_run(); 2837 } 2838 break; 2839 2840 case HCI_EVENT_LE_META: 2841 switch (packet[2]) { 2842 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2843 2844 log_info("sm: connected"); 2845 2846 if (packet[3]) return; // connection failed 2847 2848 con_handle = little_endian_read_16(packet, 4); 2849 sm_conn = sm_get_connection_for_handle(con_handle); 2850 if (!sm_conn) break; 2851 2852 sm_conn->sm_handle = con_handle; 2853 sm_conn->sm_role = packet[6]; 2854 sm_conn->sm_peer_addr_type = packet[7]; 2855 reverse_bd_addr(&packet[8], 2856 sm_conn->sm_peer_address); 2857 2858 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 2859 2860 // reset security properties 2861 sm_conn->sm_connection_encrypted = 0; 2862 sm_conn->sm_connection_authenticated = 0; 2863 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 2864 sm_conn->sm_le_db_index = -1; 2865 2866 // prepare CSRK lookup (does not involve setup) 2867 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 2868 2869 // just connected -> everything else happens in sm_run() 2870 if (sm_conn->sm_role){ 2871 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 2872 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 2873 if (sm_slave_request_security) { 2874 // request security if requested by app 2875 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2876 } else { 2877 // otherwise, wait for pairing request 2878 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2879 } 2880 } 2881 break; 2882 } else { 2883 // master 2884 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2885 } 2886 break; 2887 2888 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 2889 con_handle = little_endian_read_16(packet, 3); 2890 sm_conn = sm_get_connection_for_handle(con_handle); 2891 if (!sm_conn) break; 2892 2893 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 2894 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 2895 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 2896 break; 2897 } 2898 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 2899 // PH2 SEND LTK as we need to exchange keys in PH3 2900 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2901 break; 2902 } 2903 2904 // store rand and ediv 2905 reverse_64(&packet[5], sm_conn->sm_local_rand); 2906 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 2907 2908 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 2909 // potentially stored LTK is from the master 2910 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 2911 sm_start_calculating_ltk_from_ediv_and_rand(sm_conn); 2912 break; 2913 } 2914 2915 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2916 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 2917 #else 2918 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 2919 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 2920 #endif 2921 break; 2922 2923 default: 2924 break; 2925 } 2926 break; 2927 2928 case HCI_EVENT_ENCRYPTION_CHANGE: 2929 con_handle = little_endian_read_16(packet, 3); 2930 sm_conn = sm_get_connection_for_handle(con_handle); 2931 if (!sm_conn) break; 2932 2933 sm_conn->sm_connection_encrypted = packet[5]; 2934 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 2935 sm_conn->sm_actual_encryption_key_size); 2936 log_info("event handler, state %u", sm_conn->sm_engine_state); 2937 if (!sm_conn->sm_connection_encrypted) break; 2938 // continue if part of initial pairing 2939 switch (sm_conn->sm_engine_state){ 2940 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2941 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2942 sm_done_for_handle(sm_conn->sm_handle); 2943 break; 2944 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2945 if (sm_conn->sm_role){ 2946 // slave 2947 if (setup->sm_use_secure_connections){ 2948 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2949 } else { 2950 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2951 } 2952 } else { 2953 // master 2954 if (sm_key_distribution_all_received(sm_conn)){ 2955 // skip receiving keys as there are none 2956 sm_key_distribution_handle_all_received(sm_conn); 2957 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2958 } else { 2959 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2960 } 2961 } 2962 break; 2963 default: 2964 break; 2965 } 2966 break; 2967 2968 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 2969 con_handle = little_endian_read_16(packet, 3); 2970 sm_conn = sm_get_connection_for_handle(con_handle); 2971 if (!sm_conn) break; 2972 2973 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 2974 log_info("event handler, state %u", sm_conn->sm_engine_state); 2975 // continue if part of initial pairing 2976 switch (sm_conn->sm_engine_state){ 2977 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2978 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2979 sm_done_for_handle(sm_conn->sm_handle); 2980 break; 2981 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2982 if (sm_conn->sm_role){ 2983 // slave 2984 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2985 } else { 2986 // master 2987 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2988 } 2989 break; 2990 default: 2991 break; 2992 } 2993 break; 2994 2995 2996 case HCI_EVENT_DISCONNECTION_COMPLETE: 2997 con_handle = little_endian_read_16(packet, 3); 2998 sm_done_for_handle(con_handle); 2999 sm_conn = sm_get_connection_for_handle(con_handle); 3000 if (!sm_conn) break; 3001 3002 // delete stored bonding on disconnect with authentication failure in ph0 3003 if (sm_conn->sm_role == 0 3004 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3005 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3006 le_device_db_remove(sm_conn->sm_le_db_index); 3007 } 3008 3009 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3010 sm_conn->sm_handle = 0; 3011 break; 3012 3013 case HCI_EVENT_COMMAND_COMPLETE: 3014 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 3015 sm_handle_encryption_result(&packet[6]); 3016 break; 3017 } 3018 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 3019 sm_handle_random_result(&packet[6]); 3020 break; 3021 } 3022 break; 3023 default: 3024 break; 3025 } 3026 break; 3027 default: 3028 break; 3029 } 3030 3031 sm_run(); 3032 } 3033 3034 static inline int sm_calc_actual_encryption_key_size(int other){ 3035 if (other < sm_min_encryption_key_size) return 0; 3036 if (other < sm_max_encryption_key_size) return other; 3037 return sm_max_encryption_key_size; 3038 } 3039 3040 3041 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3042 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3043 switch (method){ 3044 case JUST_WORKS: 3045 case NK_BOTH_INPUT: 3046 return 1; 3047 default: 3048 return 0; 3049 } 3050 } 3051 // responder 3052 3053 static int sm_passkey_used(stk_generation_method_t method){ 3054 switch (method){ 3055 case PK_RESP_INPUT: 3056 return 1; 3057 default: 3058 return 0; 3059 } 3060 } 3061 #endif 3062 3063 /** 3064 * @return ok 3065 */ 3066 static int sm_validate_stk_generation_method(void){ 3067 // check if STK generation method is acceptable by client 3068 switch (setup->sm_stk_generation_method){ 3069 case JUST_WORKS: 3070 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3071 case PK_RESP_INPUT: 3072 case PK_INIT_INPUT: 3073 case OK_BOTH_INPUT: 3074 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3075 case OOB: 3076 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3077 case NK_BOTH_INPUT: 3078 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3079 return 1; 3080 default: 3081 return 0; 3082 } 3083 } 3084 3085 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3086 3087 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3088 sm_run(); 3089 } 3090 3091 if (packet_type != SM_DATA_PACKET) return; 3092 3093 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3094 if (!sm_conn) return; 3095 3096 if (packet[0] == SM_CODE_PAIRING_FAILED){ 3097 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3098 return; 3099 } 3100 3101 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 3102 3103 int err; 3104 3105 if (packet[0] == SM_CODE_KEYPRESS_NOTIFICATION){ 3106 uint8_t buffer[5]; 3107 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3108 buffer[1] = 3; 3109 little_endian_store_16(buffer, 2, con_handle); 3110 buffer[4] = packet[1]; 3111 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3112 return; 3113 } 3114 3115 switch (sm_conn->sm_engine_state){ 3116 3117 // a sm timeout requries a new physical connection 3118 case SM_GENERAL_TIMEOUT: 3119 return; 3120 3121 // Initiator 3122 case SM_INITIATOR_CONNECTED: 3123 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3124 sm_pdu_received_in_wrong_state(sm_conn); 3125 break; 3126 } 3127 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 3128 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3129 break; 3130 } 3131 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 3132 sm_key_t ltk; 3133 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 3134 if (!sm_is_null_key(ltk)){ 3135 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3136 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3137 } else { 3138 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3139 } 3140 break; 3141 } 3142 // otherwise, store security request 3143 sm_conn->sm_security_request_received = 1; 3144 break; 3145 3146 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3147 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 3148 sm_pdu_received_in_wrong_state(sm_conn); 3149 break; 3150 } 3151 // store pairing request 3152 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3153 err = sm_stk_generation_init(sm_conn); 3154 if (err){ 3155 setup->sm_pairing_failed_reason = err; 3156 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3157 break; 3158 } 3159 3160 // generate random number first, if we need to show passkey 3161 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3162 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 3163 break; 3164 } 3165 3166 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3167 if (setup->sm_use_secure_connections){ 3168 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3169 if (setup->sm_stk_generation_method == JUST_WORKS){ 3170 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3171 sm_trigger_user_response(sm_conn); 3172 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3173 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3174 } 3175 } else { 3176 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3177 } 3178 break; 3179 } 3180 #endif 3181 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3182 sm_trigger_user_response(sm_conn); 3183 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3184 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3185 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3186 } 3187 break; 3188 3189 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3190 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3191 sm_pdu_received_in_wrong_state(sm_conn); 3192 break; 3193 } 3194 3195 // store s_confirm 3196 reverse_128(&packet[1], setup->sm_peer_confirm); 3197 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3198 break; 3199 3200 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3201 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3202 sm_pdu_received_in_wrong_state(sm_conn); 3203 break;; 3204 } 3205 3206 // received random value 3207 reverse_128(&packet[1], setup->sm_peer_random); 3208 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3209 break; 3210 3211 // Responder 3212 case SM_RESPONDER_IDLE: 3213 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3214 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3215 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 3216 sm_pdu_received_in_wrong_state(sm_conn); 3217 break;; 3218 } 3219 3220 // store pairing request 3221 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3222 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3223 break; 3224 3225 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3226 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3227 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 3228 sm_pdu_received_in_wrong_state(sm_conn); 3229 break; 3230 } 3231 3232 // store public key for DH Key calculation 3233 reverse_256(&packet[01], setup->sm_peer_qx); 3234 reverse_256(&packet[33], setup->sm_peer_qy); 3235 3236 #ifdef USE_MBEDTLS_FOR_ECDH 3237 // validate public key 3238 mbedtls_ecp_point Q; 3239 mbedtls_ecp_point_init( &Q ); 3240 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 3241 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 3242 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 3243 err = mbedtls_ecp_check_pubkey(&mbedtls_ec_group, &Q); 3244 mbedtls_ecp_point_free( & Q); 3245 if (err){ 3246 log_error("sm: peer public key invalid %x", err); 3247 // uses "unspecified reason", there is no "public key invalid" error code 3248 sm_pdu_received_in_wrong_state(sm_conn); 3249 break; 3250 } 3251 3252 #endif 3253 if (sm_conn->sm_role){ 3254 // responder 3255 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3256 } else { 3257 // initiator 3258 // stk generation method 3259 // passkey entry: notify app to show passkey or to request passkey 3260 switch (setup->sm_stk_generation_method){ 3261 case JUST_WORKS: 3262 case NK_BOTH_INPUT: 3263 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3264 break; 3265 case PK_RESP_INPUT: 3266 sm_sc_start_calculating_local_confirm(sm_conn); 3267 break; 3268 case PK_INIT_INPUT: 3269 case OK_BOTH_INPUT: 3270 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3271 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3272 break; 3273 } 3274 sm_sc_start_calculating_local_confirm(sm_conn); 3275 break; 3276 case OOB: 3277 // TODO: implement SC OOB 3278 break; 3279 } 3280 } 3281 break; 3282 3283 case SM_SC_W4_CONFIRMATION: 3284 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3285 sm_pdu_received_in_wrong_state(sm_conn); 3286 break; 3287 } 3288 // received confirm value 3289 reverse_128(&packet[1], setup->sm_peer_confirm); 3290 3291 if (sm_conn->sm_role){ 3292 // responder 3293 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3294 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3295 // still waiting for passkey 3296 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3297 break; 3298 } 3299 } 3300 sm_sc_start_calculating_local_confirm(sm_conn); 3301 } else { 3302 // initiator 3303 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3304 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3305 } else { 3306 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3307 } 3308 } 3309 break; 3310 3311 case SM_SC_W4_PAIRING_RANDOM: 3312 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3313 sm_pdu_received_in_wrong_state(sm_conn); 3314 break; 3315 } 3316 3317 // received random value 3318 reverse_128(&packet[1], setup->sm_peer_nonce); 3319 3320 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3321 // only check for JUST WORK/NC in initiator role AND passkey entry 3322 if (sm_conn->sm_role || sm_passkey_used(setup->sm_stk_generation_method)) { 3323 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3324 } 3325 3326 sm_sc_state_after_receiving_random(sm_conn); 3327 break; 3328 3329 case SM_SC_W2_CALCULATE_G2: 3330 case SM_SC_W4_CALCULATE_G2: 3331 case SM_SC_W2_CALCULATE_F5_SALT: 3332 case SM_SC_W4_CALCULATE_F5_SALT: 3333 case SM_SC_W2_CALCULATE_F5_MACKEY: 3334 case SM_SC_W4_CALCULATE_F5_MACKEY: 3335 case SM_SC_W2_CALCULATE_F5_LTK: 3336 case SM_SC_W4_CALCULATE_F5_LTK: 3337 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3338 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3339 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3340 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 3341 sm_pdu_received_in_wrong_state(sm_conn); 3342 break; 3343 } 3344 // store DHKey Check 3345 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3346 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3347 3348 // have we been only waiting for dhkey check command? 3349 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3350 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3351 } 3352 break; 3353 #endif 3354 3355 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3356 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3357 sm_pdu_received_in_wrong_state(sm_conn); 3358 break; 3359 } 3360 3361 // received confirm value 3362 reverse_128(&packet[1], setup->sm_peer_confirm); 3363 3364 // notify client to hide shown passkey 3365 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3366 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3367 } 3368 3369 // handle user cancel pairing? 3370 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3371 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 3372 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3373 break; 3374 } 3375 3376 // wait for user action? 3377 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3378 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3379 break; 3380 } 3381 3382 // calculate and send local_confirm 3383 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3384 break; 3385 3386 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3387 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3388 sm_pdu_received_in_wrong_state(sm_conn); 3389 break;; 3390 } 3391 3392 // received random value 3393 reverse_128(&packet[1], setup->sm_peer_random); 3394 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3395 break; 3396 3397 case SM_PH3_RECEIVE_KEYS: 3398 switch(packet[0]){ 3399 case SM_CODE_ENCRYPTION_INFORMATION: 3400 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3401 reverse_128(&packet[1], setup->sm_peer_ltk); 3402 break; 3403 3404 case SM_CODE_MASTER_IDENTIFICATION: 3405 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3406 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3407 reverse_64(&packet[3], setup->sm_peer_rand); 3408 break; 3409 3410 case SM_CODE_IDENTITY_INFORMATION: 3411 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3412 reverse_128(&packet[1], setup->sm_peer_irk); 3413 break; 3414 3415 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3416 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3417 setup->sm_peer_addr_type = packet[1]; 3418 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3419 break; 3420 3421 case SM_CODE_SIGNING_INFORMATION: 3422 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3423 reverse_128(&packet[1], setup->sm_peer_csrk); 3424 break; 3425 default: 3426 // Unexpected PDU 3427 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3428 break; 3429 } 3430 // done with key distribution? 3431 if (sm_key_distribution_all_received(sm_conn)){ 3432 3433 sm_key_distribution_handle_all_received(sm_conn); 3434 3435 if (sm_conn->sm_role){ 3436 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3437 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3438 } else { 3439 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3440 sm_done_for_handle(sm_conn->sm_handle); 3441 } 3442 } else { 3443 if (setup->sm_use_secure_connections){ 3444 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3445 } else { 3446 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3447 } 3448 } 3449 } 3450 break; 3451 default: 3452 // Unexpected PDU 3453 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3454 break; 3455 } 3456 3457 // try to send preparared packet 3458 sm_run(); 3459 } 3460 3461 // Security Manager Client API 3462 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3463 sm_get_oob_data = get_oob_data_callback; 3464 } 3465 3466 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3467 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3468 } 3469 3470 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3471 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3472 } 3473 3474 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3475 sm_min_encryption_key_size = min_size; 3476 sm_max_encryption_key_size = max_size; 3477 } 3478 3479 void sm_set_authentication_requirements(uint8_t auth_req){ 3480 sm_auth_req = auth_req; 3481 } 3482 3483 void sm_set_io_capabilities(io_capability_t io_capability){ 3484 sm_io_capabilities = io_capability; 3485 } 3486 3487 void sm_set_request_security(int enable){ 3488 sm_slave_request_security = enable; 3489 } 3490 3491 void sm_set_er(sm_key_t er){ 3492 memcpy(sm_persistent_er, er, 16); 3493 } 3494 3495 void sm_set_ir(sm_key_t ir){ 3496 memcpy(sm_persistent_ir, ir, 16); 3497 } 3498 3499 // Testing support only 3500 void sm_test_set_irk(sm_key_t irk){ 3501 memcpy(sm_persistent_irk, irk, 16); 3502 sm_persistent_irk_ready = 1; 3503 } 3504 3505 void sm_test_use_fixed_local_csrk(void){ 3506 test_use_fixed_local_csrk = 1; 3507 } 3508 3509 void sm_init(void){ 3510 // set some (BTstack default) ER and IR 3511 int i; 3512 sm_key_t er; 3513 sm_key_t ir; 3514 for (i=0;i<16;i++){ 3515 er[i] = 0x30 + i; 3516 ir[i] = 0x90 + i; 3517 } 3518 sm_set_er(er); 3519 sm_set_ir(ir); 3520 // defaults 3521 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3522 | SM_STK_GENERATION_METHOD_OOB 3523 | SM_STK_GENERATION_METHOD_PASSKEY 3524 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3525 3526 sm_max_encryption_key_size = 16; 3527 sm_min_encryption_key_size = 7; 3528 3529 sm_cmac_state = CMAC_IDLE; 3530 dkg_state = DKG_W4_WORKING; 3531 rau_state = RAU_W4_WORKING; 3532 sm_aes128_state = SM_AES128_IDLE; 3533 sm_address_resolution_test = -1; // no private address to resolve yet 3534 sm_address_resolution_ah_calculation_active = 0; 3535 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3536 sm_address_resolution_general_queue = NULL; 3537 3538 gap_random_adress_update_period = 15 * 60 * 1000L; 3539 3540 sm_active_connection = 0; 3541 3542 test_use_fixed_local_csrk = 0; 3543 3544 // register for HCI Events from HCI 3545 hci_event_callback_registration.callback = &sm_event_packet_handler; 3546 hci_add_event_handler(&hci_event_callback_registration); 3547 3548 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3549 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3550 3551 #ifdef USE_MBEDTLS_FOR_ECDH 3552 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 3553 3554 #ifndef HAVE_MALLOC 3555 sm_mbedtls_allocator_init(mbedtls_memory_buffer, sizeof(mbedtls_memory_buffer)); 3556 #endif 3557 mbedtls_ecp_group_init(&mbedtls_ec_group); 3558 mbedtls_ecp_group_load(&mbedtls_ec_group, MBEDTLS_ECP_DP_SECP256R1); 3559 3560 #if 0 3561 // test 3562 sm_test_use_fixed_ec_keypair(); 3563 if (sm_have_ec_keypair){ 3564 printf("test dhkey check\n"); 3565 sm_key256_t dhkey; 3566 memcpy(setup->sm_peer_qx, ec_qx, 32); 3567 memcpy(setup->sm_peer_qy, ec_qy, 32); 3568 sm_sc_calculate_dhkey(dhkey); 3569 } 3570 #endif 3571 #endif 3572 } 3573 3574 void sm_use_fixed_ec_keypair(uint8_t * qx, uint8_t * qy, uint8_t * d){ 3575 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3576 memcpy(ec_qx, qx, 32); 3577 memcpy(ec_qy, qy, 32); 3578 memcpy(ec_d, d, 32); 3579 sm_have_ec_keypair = 1; 3580 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3581 #endif 3582 } 3583 3584 void sm_test_use_fixed_ec_keypair(void){ 3585 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3586 #ifdef USE_MBEDTLS_FOR_ECDH 3587 // use test keypair from spec 3588 mbedtls_mpi x; 3589 mbedtls_mpi_init(&x); 3590 mbedtls_mpi_read_string( &x, 16, "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"); 3591 mbedtls_mpi_write_binary(&x, ec_d, 32); 3592 mbedtls_mpi_read_string( &x, 16, "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"); 3593 mbedtls_mpi_write_binary(&x, ec_qx, 32); 3594 mbedtls_mpi_read_string( &x, 16, "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"); 3595 mbedtls_mpi_write_binary(&x, ec_qy, 32); 3596 mbedtls_mpi_free(&x); 3597 #endif 3598 sm_have_ec_keypair = 1; 3599 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3600 #endif 3601 } 3602 3603 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3604 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3605 if (!hci_con) return NULL; 3606 return &hci_con->sm_connection; 3607 } 3608 3609 // @returns 0 if not encrypted, 7-16 otherwise 3610 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3611 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3612 if (!sm_conn) return 0; // wrong connection 3613 if (!sm_conn->sm_connection_encrypted) return 0; 3614 return sm_conn->sm_actual_encryption_key_size; 3615 } 3616 3617 int sm_authenticated(hci_con_handle_t con_handle){ 3618 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3619 if (!sm_conn) return 0; // wrong connection 3620 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3621 return sm_conn->sm_connection_authenticated; 3622 } 3623 3624 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3625 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3626 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3627 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3628 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3629 return sm_conn->sm_connection_authorization_state; 3630 } 3631 3632 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3633 switch (sm_conn->sm_engine_state){ 3634 case SM_GENERAL_IDLE: 3635 case SM_RESPONDER_IDLE: 3636 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3637 sm_run(); 3638 break; 3639 default: 3640 break; 3641 } 3642 } 3643 3644 /** 3645 * @brief Trigger Security Request 3646 */ 3647 void sm_send_security_request(hci_con_handle_t con_handle){ 3648 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3649 if (!sm_conn) return; 3650 sm_send_security_request_for_connection(sm_conn); 3651 } 3652 3653 // request pairing 3654 void sm_request_pairing(hci_con_handle_t con_handle){ 3655 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3656 if (!sm_conn) return; // wrong connection 3657 3658 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3659 if (sm_conn->sm_role){ 3660 sm_send_security_request_for_connection(sm_conn); 3661 } else { 3662 // used as a trigger to start central/master/initiator security procedures 3663 uint16_t ediv; 3664 sm_key_t ltk; 3665 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3666 switch (sm_conn->sm_irk_lookup_state){ 3667 case IRK_LOOKUP_FAILED: 3668 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3669 break; 3670 case IRK_LOOKUP_SUCCEEDED: 3671 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, ltk, NULL, NULL, NULL); 3672 if (!sm_is_null_key(ltk) || ediv){ 3673 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3674 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3675 } else { 3676 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3677 } 3678 break; 3679 default: 3680 sm_conn->sm_bonding_requested = 1; 3681 break; 3682 } 3683 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3684 sm_conn->sm_bonding_requested = 1; 3685 } 3686 } 3687 sm_run(); 3688 } 3689 3690 // called by client app on authorization request 3691 void sm_authorization_decline(hci_con_handle_t con_handle){ 3692 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3693 if (!sm_conn) return; // wrong connection 3694 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3695 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3696 } 3697 3698 void sm_authorization_grant(hci_con_handle_t con_handle){ 3699 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3700 if (!sm_conn) return; // wrong connection 3701 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3702 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3703 } 3704 3705 // GAP Bonding API 3706 3707 void sm_bonding_decline(hci_con_handle_t con_handle){ 3708 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3709 if (!sm_conn) return; // wrong connection 3710 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3711 3712 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3713 switch (setup->sm_stk_generation_method){ 3714 case PK_RESP_INPUT: 3715 case PK_INIT_INPUT: 3716 case OK_BOTH_INPUT: 3717 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3718 break; 3719 case NK_BOTH_INPUT: 3720 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3721 break; 3722 case JUST_WORKS: 3723 case OOB: 3724 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3725 break; 3726 } 3727 } 3728 sm_run(); 3729 } 3730 3731 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3732 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3733 if (!sm_conn) return; // wrong connection 3734 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3735 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3736 if (setup->sm_use_secure_connections){ 3737 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3738 } else { 3739 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3740 } 3741 } 3742 3743 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3744 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3745 sm_sc_prepare_dhkey_check(sm_conn); 3746 } 3747 #endif 3748 3749 sm_run(); 3750 } 3751 3752 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3753 // for now, it's the same 3754 sm_just_works_confirm(con_handle); 3755 } 3756 3757 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3758 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3759 if (!sm_conn) return; // wrong connection 3760 sm_reset_tk(); 3761 big_endian_store_32(setup->sm_tk, 12, passkey); 3762 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3763 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3764 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3765 } 3766 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3767 memcpy(setup->sm_ra, setup->sm_tk, 16); 3768 memcpy(setup->sm_rb, setup->sm_tk, 16); 3769 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3770 sm_sc_start_calculating_local_confirm(sm_conn); 3771 } 3772 #endif 3773 sm_run(); 3774 } 3775 3776 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 3777 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3778 if (!sm_conn) return; // wrong connection 3779 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 3780 setup->sm_keypress_notification = action; 3781 sm_run(); 3782 } 3783 3784 /** 3785 * @brief Identify device in LE Device DB 3786 * @param handle 3787 * @returns index from le_device_db or -1 if not found/identified 3788 */ 3789 int sm_le_device_index(hci_con_handle_t con_handle ){ 3790 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3791 if (!sm_conn) return -1; 3792 return sm_conn->sm_le_db_index; 3793 } 3794 3795 // GAP LE API 3796 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 3797 gap_random_address_update_stop(); 3798 gap_random_adress_type = random_address_type; 3799 if (random_address_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3800 gap_random_address_update_start(); 3801 gap_random_address_trigger(); 3802 } 3803 3804 gap_random_address_type_t gap_random_address_get_mode(void){ 3805 return gap_random_adress_type; 3806 } 3807 3808 void gap_random_address_set_update_period(int period_ms){ 3809 gap_random_adress_update_period = period_ms; 3810 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3811 gap_random_address_update_stop(); 3812 gap_random_address_update_start(); 3813 } 3814 3815 void gap_random_address_set(bd_addr_t addr){ 3816 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_OFF); 3817 memcpy(sm_random_address, addr, 6); 3818 rau_state = RAU_SET_ADDRESS; 3819 sm_run(); 3820 } 3821 3822 /* 3823 * @brief Set Advertisement Paramters 3824 * @param adv_int_min 3825 * @param adv_int_max 3826 * @param adv_type 3827 * @param direct_address_type 3828 * @param direct_address 3829 * @param channel_map 3830 * @param filter_policy 3831 * 3832 * @note own_address_type is used from gap_random_address_set_mode 3833 */ 3834 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 3835 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 3836 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, gap_random_adress_type, 3837 direct_address_typ, direct_address, channel_map, filter_policy); 3838 } 3839 3840